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diff --git a/man-pages-posix-2003/man1p/ex.1p b/man-pages-posix-2003/man1p/ex.1p new file mode 100644 index 0000000..474894a --- /dev/null +++ b/man-pages-posix-2003/man1p/ex.1p @@ -0,0 +1,6061 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "EX" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" ex +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.SH NAME +ex \- text editor +.SH SYNOPSIS +.LP +\fBex\fP \fB[\fP\fB-rR\fP\fB][\fP\fB-s | -v\fP\fB][\fP\fB-c\fP +\fIcommand\fP\fB][\fP\fB-t\fP \fItagstring\fP\fB][\fP\fB-w\fP \fIsize\fP\fB][\fP\fIfile\fP +\fB\&...\fP\fB]\fP\fB\fP +.SH DESCRIPTION +.LP +The \fIex\fP utility is a line-oriented text editor. There are two +other modes of the editor-open and visual-in which +screen-oriented editing is available. This is described more fully +by the \fIex\fP \fBopen\fP and \fBvisual\fP commands and in +\fIvi\fP . +.LP +This section uses the term \fIedit buffer\fP to describe the current +working text. No specific implementation is implied by +this term. All editing changes are performed on the edit buffer, and +no changes to it shall affect any file until an editor command +writes the file. +.LP +Certain terminals do not have all the capabilities necessary to support +the complete \fIex\fP definition, such as the +full-screen editing commands ( \fIvisual mode\fP or \fIopen mode\fP). +When these commands cannot be supported on such terminals, +this condition shall not produce an error message such as "not an +editor command" or report a syntax error. The implementation +may either accept the commands and produce results on the screen that +are the result of an unsuccessful attempt to meet the +requirements of this volume of IEEE\ Std\ 1003.1-2001 or report an +error describing the terminal-related deficiency. +.SH OPTIONS +.LP +The \fIex\fP utility shall conform to the Base Definitions volume +of IEEE\ Std\ 1003.1-2001, Section 12.2, Utility Syntax Guidelines. +.LP +The following options shall be supported: +.TP 7 +\fB-c\ \fP \fIcommand\fP +Specify an initial command to be executed in the first edit buffer +loaded from an existing file (see the EXTENDED DESCRIPTION +section). Implementations may support more than a single \fB-c\fP +option. In such implementations, the specified commands shall be +executed in the order specified on the command line. +.TP 7 +\fB-r\fP +Recover the named files (see the EXTENDED DESCRIPTION section). Recovery +information for a file shall be saved during an editor +or system crash (for example, when the editor is terminated by a signal +which the editor can catch), or after the use of an +\fIex\fP \fBpreserve\fP command. +.LP +A \fIcrash\fP in this context is an unexpected failure of the system +or utility that requires restarting the failed system or +utility. A system crash implies that any utilities running at the +time also crash. In the case of an editor or system crash, the +number of changes to the edit buffer (since the most recent \fBpreserve\fP +command) that will be recovered is unspecified. +.LP +If no \fIfile\fP operands are given and the \fB-t\fP option is not +specified, all other options, the \fIEXINIT\fP variable, +and any \fB.exrc\fP files shall be ignored; a list of all recoverable +files available to the invoking user shall be written, and +the editor shall exit normally without further action. +.TP 7 +\fB-R\fP +Set \fBreadonly\fP edit option. +.TP 7 +\fB-s\fP +Prepare \fIex\fP for batch use by taking the following actions: +.RS +.IP " *" 3 +Suppress writing prompts and informational (but not diagnostic) messages. +.LP +.IP " *" 3 +Ignore the value of \fITERM\fP and any implementation default terminal +type and assume the terminal is a type incapable of +supporting open or visual modes; see the \fBvisual\fP command and +the description of \fIvi\fP . +.LP +.IP " *" 3 +Suppress the use of the \fIEXINIT\fP environment variable and the +reading of any \fB.exrc\fP file; see the EXTENDED +DESCRIPTION section. +.LP +.IP " *" 3 +Suppress autoindentation, ignoring the value of the \fBautoindent\fP +edit option. +.LP +.RE +.TP 7 +\fB-t\ \fP \fItagstring\fP +Edit the file containing the specified \fItagstring\fP; see \fIctags\fP +\&. The tags feature +represented by \fB-t\fP \fItagstring\fP and the \fBtag\fP command +is optional. It shall be provided on any system that also +provides a conforming implementation of \fIctags\fP; otherwise, the +use of \fB-t\fP +produces undefined results. On any system, it shall be an error to +specify more than a single \fB-t\fP option. +.TP 7 +\fB-v\fP +Begin in visual mode (see \fIvi\fP ). +.TP 7 +\fB-w\ \fP \fIsize\fP +Set the value of the \fIwindow\fP editor option to \fIsize\fP. +.sp +.SH OPERANDS +.LP +The following operand shall be supported: +.TP 7 +\fIfile\fP +A pathname of a file to be edited. +.sp +.SH STDIN +.LP +The standard input consists of a series of commands and input text, +as described in the EXTENDED DESCRIPTION section. The +implementation may limit each line of standard input to a length of +{LINE_MAX}. +.LP +If the standard input is not a terminal device, it shall be as if +the \fB-s\fP option had been specified. +.LP +If a read from the standard input returns an error, or if the editor +detects an end-of-file condition from the standard input, +it shall be equivalent to a SIGHUP asynchronous event. +.SH INPUT FILES +.LP +Input files shall be text files or files that would be text files +except for an incomplete last line that is not longer than +{LINE_MAX}-1 bytes in length and contains no NUL characters. By default, +any incomplete last line shall be treated as if it had a +trailing <newline>. The editing of other forms of files may optionally +be allowed by \fIex\fP implementations. +.LP +The \fB.exrc\fP files and source files shall be text files consisting +of \fIex\fP commands; see the EXTENDED DESCRIPTION +section. +.LP +By default, the editor shall read lines from the files to be edited +without interpreting any of those lines as any form of +editor command. +.SH ENVIRONMENT VARIABLES +.LP +The following environment variables shall affect the execution of +\fIex\fP: +.TP 7 +\fICOLUMNS\fP +Override the system-selected horizontal screen size. See the Base +Definitions volume of IEEE\ Std\ 1003.1-2001, Chapter 8, Environment +Variables for valid values and results when it is unset or null. +.TP 7 +\fIEXINIT\fP +Determine a list of \fIex\fP commands that are executed on editor +start-up. See the EXTENDED DESCRIPTION section for more +details of the initialization phase. +.TP 7 +\fIHOME\fP +Determine a pathname of a directory that shall be searched for an +editor start-up file named \fB.exrc\fP; see the EXTENDED +DESCRIPTION section. +.TP 7 +\fILANG\fP +Provide a default value for the internationalization variables that +are unset or null. (See the Base Definitions volume of +IEEE\ Std\ 1003.1-2001, Section 8.2, Internationalization Variables +for +the precedence of internationalization variables used to determine +the values of locale categories.) +.TP 7 +\fILC_ALL\fP +If set to a non-empty string value, override the values of all the +other internationalization variables. +.TP 7 +\fILC_COLLATE\fP +.sp +Determine the locale for the behavior of ranges, equivalence classes, +and multi-character collating elements within regular +expressions. +.TP 7 +\fILC_CTYPE\fP +Determine the locale for the interpretation of sequences of bytes +of text data as characters (for example, single-byte as +opposed to multi-byte characters in arguments and input files), the +behavior of character classes within regular expressions, the +classification of characters as uppercase or lowercase letters, the +case conversion of letters, and the detection of word +boundaries. +.TP 7 +\fILC_MESSAGES\fP +Determine the locale that should be used to affect the format and +contents of diagnostic messages written to standard +error. +.TP 7 +\fILINES\fP +Override the system-selected vertical screen size, used as the number +of lines in a screenful and the vertical screen size in +visual mode. See the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +Chapter 8, +Environment Variables for valid values and results when it is unset +or null. +.TP 7 +\fINLSPATH\fP +Determine the location of message catalogs for the processing of \fILC_MESSAGES +\&.\fP +.TP 7 +\fIPATH\fP +Determine the search path for the shell command specified in the \fIex\fP +editor commands \fB!\fP, \fBshell\fP, \fBread\fP, +and \fBwrite\fP, and the open and visual mode command \fB!\fP; see +the description of command search and execution in \fICommand Search +and Execution\fP . +.TP 7 +\fISHELL\fP +Determine the preferred command line interpreter for use as the default +value of the \fBshell\fP edit option. +.TP 7 +\fITERM\fP +Determine the name of the terminal type. If this variable is unset +or null, an unspecified default terminal type shall be +used. +.sp +.SH ASYNCHRONOUS EVENTS +.LP +The following term is used in this and following sections to specify +command and asynchronous event actions: +.TP 7 +\fIcomplete\ write\fP +.sp +A complete write is a write of the entire contents of the edit buffer +to a file of a type other than a terminal device, or the +saving of the edit buffer caused by the user executing the \fIex\fP +\fBpreserve\fP command. Writing the contents of the edit +buffer to a temporary file that will be removed when the editor exits +shall not be considered a complete write. +.sp +.LP +The following actions shall be taken upon receipt of signals: +.TP 7 +SIGINT +If the standard input is not a terminal device, \fIex\fP shall not +write the file or return to command or text input mode, and +shall exit with a non-zero exit status. +.LP +Otherwise, if executing an open or visual text input mode command, +\fIex\fP in receipt of SIGINT shall behave identically to +its receipt of the <ESC> character. +.LP +Otherwise: +.RS +.IP " 1." 4 +If executing an \fIex\fP text input mode command, all input lines +that have been completely entered shall be resolved into the +edit buffer, and any partially entered line shall be discarded. +.LP +.IP " 2." 4 +If there is a currently executing command, it shall be aborted and +a message displayed. Unless otherwise specified by the +\fIex\fP or \fIvi\fP command descriptions, it is unspecified whether +any lines modified by the +executing command appear modified, or as they were before being modified +by the executing command, in the buffer. +.LP +If the currently executing command was a motion command, its associated +command shall be discarded. +.LP +.IP " 3." 4 +If in open or visual command mode, the terminal shall be alerted. +.LP +.IP " 4." 4 +The editor shall then return to command mode. +.LP +.RE +.TP 7 +SIGCONT +The screen shall be refreshed if in open or visual mode. +.TP 7 +SIGHUP +If the edit buffer has been modified since the last complete write, +\fIex\fP shall attempt to save the edit buffer so that it +can be recovered later using the \fB-r\fP option or the \fIex\fP \fBrecover\fP +command. The editor shall not write the file or +return to command or text input mode, and shall terminate with a non-zero +exit status. +.TP 7 +SIGTERM +Refer to SIGHUP. +.sp +.LP +The action taken for all other signals is unspecified. +.SH STDOUT +.LP +The standard output shall be used only for writing prompts to the +user, for informational messages, and for writing lines from +the file. +.SH STDERR +.LP +The standard error shall be used only for diagnostic messages. +.SH OUTPUT FILES +.LP +The output from \fIex\fP shall be text files. +.SH EXTENDED DESCRIPTION +.LP +Only the \fIex\fP mode of the editor is described in this section. +See \fIvi\fP for additional editing +capabilities available in \fIex\fP. +.LP +When an error occurs, \fIex\fP shall write a message. If the terminal +supports a standout mode (such as inverse video), the +message shall be written in standout mode. If the terminal does not +support a standout mode, and the edit option \fBerrorbells\fP +is set, an alert action shall precede the error message. +.LP +By default, \fIex\fP shall start in command mode, which shall be indicated +by a \fB:\fP prompt; see the \fBprompt\fP command. +Text input mode can be entered by the \fBappend\fP, \fBinsert\fP, +or \fBchange\fP commands; it can be exited (and command mode +re-entered) by typing a period ( \fB'.'\fP ) alone at the beginning +of a line. +.SS Initialization in ex and vi +.LP +The following symbols are used in this and following sections to specify +locations in the edit buffer: +.TP 7 +\fIalternate\ and\ current\ pathnames\fP +.sp +Two pathnames, named \fIcurrent\fP and \fIalternate\fP, are maintained +by the editor. Any \fIex\fP commands that take filenames +as arguments shall set them as follows: +.RS +.IP " 1." 4 +If a \fIfile\fP argument is specified to the \fIex\fP \fBedit\fP, +\fBex\fP, or \fBrecover\fP commands, or if an \fIex\fP +\fBtag\fP command replaces the contents of the edit buffer. +.RS +.IP " a." 4 +If the command replaces the contents of the edit buffer, the current +pathname shall be set to the \fIfile\fP argument or the +file indicated by the tag, and the alternate pathname shall be set +to the previous value of the current pathname. +.LP +.IP " b." 4 +Otherwise, the alternate pathname shall be set to the \fIfile\fP argument. +.LP +.RE +.LP +.IP " 2." 4 +If a \fIfile\fP argument is specified to the \fIex\fP \fBnext\fP command: +.RS +.IP " a." 4 +If the command replaces the contents of the edit buffer, the current +pathname shall be set to the first \fIfile\fP argument, +and the alternate pathname shall be set to the previous value of the +current pathname. +.LP +.RE +.LP +.IP " 3." 4 +If a \fIfile\fP argument is specified to the \fIex\fP \fBfile\fP command, +the current pathname shall be set to the +\fIfile\fP argument, and the alternate pathname shall be set to the +previous value of the current pathname. +.LP +.IP " 4." 4 +If a \fIfile\fP argument is specified to the \fIex\fP \fBread\fP and +\fBwrite\fP commands (that is, when reading or writing +a file, and not to the program named by the \fBshell\fP edit option), +or a \fIfile\fP argument is specified to the \fIex\fP +\fBxit\fP command: +.RS +.IP " a." 4 +If the current pathname has no value, the current pathname shall be +set to the \fIfile\fP argument. +.LP +.IP " b." 4 +Otherwise, the alternate pathname shall be set to the \fIfile\fP argument. +.LP +.RE +.LP +.RE +.LP +If the alternate pathname is set to the previous value of the current +pathname when the current pathname had no previous value, +then the alternate pathname shall have no value as a result. +.TP 7 +\fIcurrent\ line\fP +.sp +The line of the edit buffer referenced by the cursor. Each command +description specifies the current line after the command has +been executed, as the \fIcurrent line value\fP. When the edit buffer +contains no lines, the current line shall be zero; see Addressing +in ex . +.TP 7 +\fIcurrent\ column\fP +.sp +The current display line column occupied by the cursor. (The columns +shall be numbered beginning at 1.) Each command description +specifies the current column after the command has been executed, +as the \fIcurrent column\fP value. This column is an +\fIideal\fP column that is remembered over the lifetime of the editor. +The actual display line column upon which the cursor rests +may be different from the current column; see the cursor positioning +discussion in \fICommand +Descriptions in vi\fP . +.TP 7 +\fIset\ to\ non-<blank>\fP +.sp +A description for a current column value, meaning that the current +column shall be set to the last display line column on which is +displayed any part of the first non- <blank> of the line. If the line +has no non- <blank> non- <newline>s, the +current column shall be set to the last display line column on which +is displayed any part of the last non- <newline> in the +line. If the line is empty, the current column shall be set to column +position 1. +.sp +.LP +The length of lines in the edit buffer may be limited to {LINE_MAX} +bytes. In open and visual mode, the length of lines in the +edit buffer may be limited to the number of characters that will fit +in the display. If either limit is exceeded during editing, an +error message shall be written. If either limit is exceeded by a line +read in from a file, an error message shall be written and +the edit session may be terminated. +.LP +If the editor stops running due to any reason other than a user command, +and the edit buffer has been modified since the last +complete write, it shall be equivalent to a SIGHUP asynchronous event. +If the system crashes, it shall be equivalent to a SIGHUP +asynchronous event. +.LP +During initialization (before the first file is copied into the edit +buffer or any user commands from the terminal are +processed) the following shall occur: +.IP " 1." 4 +If the environment variable \fIEXINIT\fP is set, the editor shall +execute the \fIex\fP commands contained in that +variable. +.LP +.IP " 2." 4 +If the \fIEXINIT\fP variable is not set, and all of the following +are true: +.RS +.IP " a." 4 +The \fIHOME\fP environment variable is not null and not empty. +.LP +.IP " b." 4 +The file \fB.exrc\fP in the directory referred to by the \fIHOME\fP +environment variable: +.RS +.IP " 1." 4 +Exists +.LP +.IP " 2." 4 +Is owned by the same user ID as the real user ID of the process or +the process has appropriate privileges +.LP +.IP " 3." 4 +Is not writable by anyone other than the owner +.LP +.RE +.LP +.RE +.LP +the editor shall execute the \fIex\fP commands contained in that file. +.LP +.IP " 3." 4 +If and only if all of the following are true: +.RS +.IP " a." 4 +The current directory is not referred to by the \fIHOME\fP environment +variable. +.LP +.IP " b." 4 +A command in the \fIEXINIT\fP environment variable or a command in +the \fB.exrc\fP file in the directory referred to by the +\fIHOME\fP environment variable sets the editor option \fBexrc\fP. +.LP +.IP " c." 4 +The \fB.exrc\fP file in the current directory: +.RS +.IP " 1." 4 +Exists +.LP +.IP " 2." 4 +Is owned by the same user ID as the real user ID of the process, or +by one of a set of implementation-defined user IDs +.LP +.IP " 3." 4 +Is not writable by anyone other than the owner +.LP +.RE +.LP +.RE +.LP +the editor shall attempt to execute the \fIex\fP commands contained +in that file. +.LP +.LP +Lines in any \fB.exrc\fP file that are blank lines shall be ignored. +If any \fB.exrc\fP file exists, but is not read for +ownership or permission reasons, it shall be an error. +.LP +After the \fIEXINIT\fP variable and any \fB.exrc\fP files are processed, +the first file specified by the user shall be edited, +as follows: +.IP " 1." 4 +If the user specified the \fB-t\fP option, the effect shall be as +if the \fIex\fP \fBtag\fP command was entered with the +specified argument, with the exception that if tag processing does +not result in a file to edit, the effect shall be as described +in step 3. below. +.LP +.IP " 2." 4 +Otherwise, if the user specified any command line \fIfile\fP arguments, +the effect shall be as if the \fIex\fP \fBedit\fP +command was entered with the first of those arguments as its \fIfile\fP +argument. +.LP +.IP " 3." 4 +Otherwise, the effect shall be as if the \fIex\fP \fBedit\fP command +was entered with a nonexistent filename as its +\fIfile\fP argument. It is unspecified whether this action shall set +the current pathname. In an implementation where this action +does not set the current pathname, any editor command using the current +pathname shall fail until an editor command sets the +current pathname. +.LP +.LP +If the \fB-r\fP option was specified, the first time a file in the +initial argument list or a file specified by the \fB-t\fP +option is edited, if recovery information has previously been saved +about it, that information shall be recovered and the editor +shall behave as if the contents of the edit buffer have already been +modified. If there are multiple instances of the file to be +recovered, the one most recently saved shall be recovered, and an +informational message that there are previous versions of the +file that can be recovered shall be written. If no recovery information +about a file is available, an informational message to this +effect shall be written, and the edit shall proceed as usual. +.LP +If the \fB-c\fP option was specified, the first time a file that already +exists (including a file that might not exist but for +which recovery information is available, when the \fB-r\fP option +is specified) replaces or initializes the contents of the edit +buffer, the current line shall be set to the last line of the edit +buffer, the current column shall be set to non- <blank>, +and the \fIex\fP commands specified with the \fB-c\fP option shall +be executed. In this case, the current line and current column +shall not be set as described for the command associated with the +replacement or initialization of the edit buffer contents. +However, if the \fB-t\fP option or a \fBtag\fP command is associated +with this action, the \fB-c\fP option commands shall be +executed and then the movement to the tag shall be performed. +.LP +The current argument list shall initially be set to the filenames +specified by the user on the command line. If no filenames are +specified by the user, the current argument list shall be empty. If +the \fB-t\fP option was specified, it is unspecified whether +any filename resulting from tag processing shall be prepended to the +current argument list. In the case where the filename is added +as a prefix to the current argument list, the current argument list +reference shall be set to that filename. In the case where the +filename is not added as a prefix to the current argument list, the +current argument list reference shall logically be located +before the first of the filenames specified on the command line (for +example, a subsequent \fIex\fP \fBnext\fP command shall edit +the first filename from the command line). If the \fB-t\fP option +was not specified, the current argument list reference shall be +to the first of the filenames on the command line. +.SS Addressing in ex +.LP +Addressing in \fIex\fP relates to the current line and the current +column; the address of a line is its 1-based line number, +the address of a column is its 1-based count from the beginning of +the line. Generally, the current line is the last line affected +by a command. The current line number is the address of the current +line. In each command description, the effect of the command on +the current line number and the current column is described. +.LP +Addresses are constructed as follows: +.IP " 1." 4 +The character \fB'.'\fP (period) shall address the current line. +.LP +.IP " 2." 4 +The character \fB'$'\fP shall address the last line of the edit buffer. +.LP +.IP " 3." 4 +The positive decimal number \fIn\fP shall address the \fIn\fPth line +of the edit buffer. +.LP +.IP " 4." 4 +The address \fB"'x"\fP refers to the line marked with the mark name +character \fB'x'\fP, which shall be a lowercase +letter from the portable character set or one of the characters \fB'`'\fP +or \fB'"\fP . It shall be an error if the line +that was marked is not currently present in the edit buffer or the +mark has not been set. Lines can be marked with the \fIex\fP +\fBmark\fP or \fBk\fP commands, or the \fIvi\fP \fBm\fP command. +.LP +.IP " 5." 4 +A regular expression enclosed by slashes ( \fB'/'\fP ) shall address +the first line found by searching forwards from the line +following the current line toward the end of the edit buffer and stopping +at the first line for which the line excluding the +terminating <newline> matches the regular expression. As stated in +Regular Expressions in ex, +an address consisting of a null regular expression delimited by slashes +\fB"//"\fP shall address the next line for which the +line excluding the terminating <newline> matches the last regular +expression encountered. In addition, the second slash can +be omitted at the end of a command line. If the \fBwrapscan\fP edit +option is set, the search shall wrap around to the beginning +of the edit buffer and continue up to and including the current line, +so that the entire edit buffer is searched. Within the +regular expression, the sequence \fB"\\/"\fP shall represent a literal +slash instead of the regular expression delimiter. +.LP +.IP " 6." 4 +A regular expression enclosed in question marks ( \fB'?'\fP ) shall +address the first line found by searching backwards from +the line preceding the current line toward the beginning of the edit +buffer and stopping at the first line for which the line +excluding the terminating <newline> matches the regular expression. +An address consisting of a null regular expression +delimited by question marks \fB"??"\fP shall address the previous +line for which the line excluding the terminating +<newline> matches the last regular expression encountered. In addition, +the second question mark can be omitted at the end of +a command line. If the \fBwrapscan\fP edit option is set, the search +shall wrap around from the beginning of the edit buffer to +the end of the edit buffer and continue up to and including the current +line, so that the entire edit buffer is searched. Within +the regular expression, the sequence \fB"\\?"\fP shall represent a +literal question mark instead of the RE delimiter. +.LP +.IP " 7." 4 +A plus sign ( \fB'+'\fP ) or a minus sign ( \fB'-'\fP ) followed by +a decimal number shall address the current line plus +or minus the number. A \fB'+'\fP or \fB'-'\fP not followed by a decimal +number shall address the current line plus or minus +1. +.LP +.LP +Addresses can be followed by zero or more address offsets, optionally +<blank>-separated. Address offsets are constructed +as follows: +.IP " 1." 4 +A \fB'+'\fP or \fB'-'\fP immediately followed by a decimal number +shall add (subtract) the indicated number of lines to +(from) the address. A \fB'+'\fP or \fB'-'\fP not followed by a decimal +number shall add (subtract) 1 to (from) the +address. +.LP +.IP " 2." 4 +A decimal number shall add the indicated number of lines to the address. +.LP +.LP +It shall not be an error for an intermediate address value to be less +than zero or greater than the last line in the edit +buffer. It shall be an error for the final address value to be less +than zero or greater than the last line in the edit buffer. +.LP +Commands take zero, one, or two addresses; see the descriptions of +\fI1addr\fP and \fI2addr\fP in Command Descriptions in ex . If more +than the required number of addresses are provided to a command that +requires zero addresses, it shall be an error. Otherwise, if more +than the required number of addresses are provided to a command, +the addresses specified first shall be evaluated and then discarded +until the maximum number of valid addresses remain. +.LP +Addresses shall be separated from each other by a comma ( \fB','\fP +) or a semicolon ( \fB';'\fP ). If no address is +specified before or after a comma or semicolon separator, it shall +be as if the address of the current line was specified before or +after the separator. In the case of a semicolon separator, the current +line ( \fB'.'\fP ) shall be set to the first address, and +only then will the next address be calculated. This feature can be +used to determine the starting line for forwards and backwards +searches (see rules 5. and 6.). +.LP +A percent sign ( \fB'%'\fP ) shall be equivalent to entering the two +addresses \fB"1,$"\fP . +.LP +Any delimiting <blank>s between addresses, address separators, or +address offsets shall be discarded. +.SS Command Line Parsing in ex +.LP +The following symbol is used in this and following sections to describe +parsing behavior: +.TP 7 +\fIescape\fP +If a character is referred to as "backslash-escaped" or " <control>-V-escaped," +it shall mean that the character +acquired or lost a special meaning by virtue of being preceded, respectively, +by a backslash or <control>-V character. Unless +otherwise specified, the escaping character shall be discarded at +that time and shall not be further considered for any +purpose. +.sp +.LP +Command-line parsing shall be done in the following steps. For each +step, characters already evaluated shall be ignored; that +is, the phrase "leading character" refers to the next character that +has not yet been evaluated. +.IP " 1." 4 +Leading colon characters shall be skipped. +.LP +.IP " 2." 4 +Leading <blank>s shall be skipped. +.LP +.IP " 3." 4 +If the leading character is a double-quote character, the characters +up to and including the next non-backslash-escaped +<newline> shall be discarded, and any subsequent characters shall +be parsed as a separate command. +.LP +.IP " 4." 4 +Leading characters that can be interpreted as addresses shall be evaluated; +see Addressing in ex +\&. +.LP +.IP " 5." 4 +Leading <blank>s shall be skipped. +.LP +.IP " 6." 4 +If the next character is a vertical-line character or a <newline>: +.RS +.IP " a." 4 +If the next character is a <newline>: +.RS +.IP " 1." 4 +If \fIex\fP is in open or visual mode, the current line shall be set +to the last address specified, if any. +.LP +.IP " 2." 4 +Otherwise, if the last command was terminated by a vertical-line character, +no action shall be taken; for example, the command +\fB"||<newline>"\fP shall execute two implied commands, not three. +.LP +.IP " 3." 4 +Otherwise, step 6.b. shall apply. +.LP +.RE +.LP +.IP " b." 4 +Otherwise, the implied command shall be the \fBprint\fP command. The +last \fB#\fP, \fBp\fP, and \fBl\fP flags specified to +any \fIex\fP command shall be remembered and shall apply to this implied +command. Executing the \fIex\fP \fBnumber\fP, +\fBprint\fP, or \fBlist\fP command shall set the remembered flags +to \fB#\fP, nothing, and \fBl\fP, respectively, plus any +other flags specified for that execution of the \fBnumber\fP, \fBprint\fP, +or \fBlist\fP command. +.LP +If \fIex\fP is not currently performing a \fBglobal\fP or \fBv\fP +command, and no address or count is specified, the current +line shall be incremented by 1 before the command is executed. If +incrementing the current line would result in an address past the +last line in the edit buffer, the command shall fail, and the increment +shall not happen. +.LP +.IP " c." 4 +The <newline> or vertical-line character shall be discarded and any +subsequent characters shall be parsed as a separate +command. +.LP +.RE +.LP +.IP " 7." 4 +The command name shall be comprised of the next character (if the +character is not alphabetic), or the next character and any +subsequent alphabetic characters (if the character is alphabetic), +with the following exceptions: +.RS +.IP " a." 4 +Commands that consist of any prefix of the characters in the command +name \fBdelete\fP, followed immediately by any of the +characters \fB'l'\fP, \fB'p'\fP, \fB'+'\fP, \fB'-'\fP, or \fB'#'\fP +shall be interpreted as a \fBdelete\fP +command, followed by a <blank>, followed by the characters that were +not part of the prefix of the \fBdelete\fP command. The +maximum number of characters shall be matched to the command name +\fBdelete\fP; for example, \fB"del"\fP shall not be treated +as \fB"de"\fP followed by the flag \fBl\fP. +.LP +.IP " b." 4 +Commands that consist of the character \fB'k'\fP, followed by a character +that can be used as the name of a mark, shall be +equivalent to the mark command followed by a <blank>, followed by +the character that followed the \fB'k'\fP . +.LP +.IP " c." 4 +Commands that consist of the character \fB's'\fP, followed by characters +that could be interpreted as valid options to the +\fBs\fP command, shall be the equivalent of the \fBs\fP command, without +any pattern or replacement values, followed by a +<blank>, followed by the characters after the \fB's'\fP . +.LP +.RE +.LP +.IP " 8." 4 +The command name shall be matched against the possible command names, +and a command name that contains a prefix matching the +characters specified by the user shall be the executed command. In +the case of commands where the characters specified by the user +could be ambiguous, the executed command shall be as follows: +.TS C +center; l l l l l l l l. +\fBa\fP \fBappend\fP n \fBnext\fP \fBt\fP t \fB\ \fP \fB\ \fP +\fBc\fP \fBchange\fP p \fBprint\fP \fBu\fP undo \fB\ \fP \fB\ \fP +\fBch\fP \fBchange\fP pr \fBprint\fP \fBun\fP undo \fB\ \fP \fB\ \fP +\fBe\fP \fBedit\fP r \fBread\fP \fBv\fP v \fB\ \fP \fB\ \fP +\fBm\fP \fBmove\fP re \fBread\fP \fBw\fP write \fB\ \fP \fB\ \fP +\fBma\fP \fBmark\fP s \fBs\fP \fB\ \fP \ \fB\ \fP \fB\ \fP +.TE +.LP +Implementation extensions with names causing similar ambiguities shall +not be checked for a match until all possible matches for +commands specified by IEEE\ Std\ 1003.1-2001 have been checked. +.LP +.IP " 9." 4 +If the command is a \fB!\fP command, or if the command is a \fBread\fP +command followed by zero or more <blank>s and a +\fB!\fP, or if the command is a \fBwrite\fP command followed by one +or more <blank>s and a \fB!\fP, the rest of the +command shall include all characters up to a non-backslash-escaped +<newline>. The <newline> shall be discarded and any +subsequent characters shall be parsed as a separate \fIex\fP command. +.LP +.IP "10." 4 +Otherwise, if the command is an \fBedit\fP, \fBex\fP, or \fBnext\fP +command, or a \fBvisual\fP command while in open or +visual mode, the next part of the command shall be parsed as follows: +.RS +.IP " a." 4 +Any \fB'!'\fP character immediately following the command shall be +skipped and be part of the command. +.LP +.IP " b." 4 +Any leading <blank>s shall be skipped and be part of the command. +.LP +.IP " c." 4 +If the next character is a \fB'+'\fP, characters up to the first +non-backslash-escaped <newline> or +non-backslash-escaped <blank> shall be skipped and be part of the +command. +.LP +.IP " d." 4 +The rest of the command shall be determined by the steps specified +in paragraph 12. +.LP +.RE +.LP +.IP "11." 4 +Otherwise, if the command is a \fBglobal\fP, \fBopen\fP, \fBs\fP, +or \fBv\fP command, the next part of the command shall be +parsed as follows: +.RS +.IP " a." 4 +Any leading <blank>s shall be skipped and be part of the command. +.LP +.IP " b." 4 +If the next character is not an alphanumeric, double-quote, <newline>, +backslash, or vertical-line character: +.RS +.IP " 1." 4 +The next character shall be used as a command delimiter. +.LP +.IP " 2." 4 +If the command is a \fBglobal\fP, \fBopen\fP, or \fBv\fP command, +characters up to the first non-backslash-escaped +<newline>, or first non-backslash-escaped delimiter character, shall +be skipped and be part of the command. +.LP +.IP " 3." 4 +If the command is an \fBs\fP command, characters up to the first non-backslash-escaped +<newline>, or second +non-backslash-escaped delimiter character, shall be skipped and be +part of the command. +.LP +.RE +.LP +.IP " c." 4 +If the command is a \fBglobal\fP or \fBv\fP command, characters up +to the first non-backslash-escaped <newline> shall be +skipped and be part of the command. +.LP +.IP " d." 4 +Otherwise, the rest of the command shall be determined by the steps +specified in paragraph 12. +.LP +.RE +.LP +.IP "12." 4 +Otherwise: +.RS +.IP " a." 4 +If the command was a \fBmap\fP, \fBunmap\fP, \fBabbreviate\fP, or +\fBunabbreviate\fP command, characters up to the first +non- <control>-V-escaped <newline>, vertical-line, or double-quote +character shall be skipped and be part of the +command. +.LP +.IP " b." 4 +Otherwise, characters up to the first non-backslash-escaped <newline>, +vertical-line, or double-quote character shall be +skipped and be part of the command. +.LP +.IP " c." 4 +If the command was an \fBappend\fP, \fBchange\fP, or \fBinsert\fP +command, and the step 12.b. ended at a vertical-line +character, any subsequent characters, up to the next non-backslash-escaped +<newline> shall be used as input text to the +command. +.LP +.IP " d." 4 +If the command was ended by a double-quote character, all subsequent +characters, up to the next non-backslash-escaped +<newline>, shall be discarded. +.LP +.IP " e." 4 +The terminating <newline> or vertical-line character shall be discarded +and any subsequent characters shall be parsed as a +separate \fIex\fP command. +.LP +.RE +.LP +.LP +Command arguments shall be parsed as described by the Synopsis and +Description of each individual \fIex\fP command. This +parsing shall not be <blank>-sensitive, except for the \fB!\fP argument, +which must follow the command name without +intervening <blank>s, and where it would otherwise be ambiguous. For +example, \fIcount\fP and \fIflag\fP arguments need not +be <blank>-separated because \fB"d22p"\fP is not ambiguous, but \fIfile\fP +arguments to the \fIex\fP \fBnext\fP command +must be separated by one or more <blank>s. Any <blank> in command +arguments for the \fBabbreviate\fP, +\fBunabbreviate\fP, \fBmap\fP, and \fBunmap\fP commands can be <control>-V-escaped, +in which case the <blank> shall +not be used as an argument delimiter. Any <blank> in the command argument +for any other command can be backslash-escaped, in +which case that <blank> shall not be used as an argument delimiter. +.LP +Within command arguments for the \fBabbreviate\fP, \fBunabbreviate\fP, +\fBmap\fP, and \fBunmap\fP commands, any character +can be <control>-V-escaped. All such escaped characters shall be treated +literally and shall have no special meaning. Within +command arguments for all other \fIex\fP commands that are not regular +expressions or replacement strings, any character that +would otherwise have a special meaning can be backslash-escaped. Escaped +characters shall be treated literally, without special +meaning as shell expansion characters or \fB'!'\fP, \fB'%'\fP, and +\fB'#'\fP expansion characters. See Regular Expressions in ex and +Replacement Strings in ex for descriptions of +command arguments that are regular expressions or replacement strings. +.LP +Non-backslash-escaped \fB'%'\fP characters appearing in \fIfile\fP +arguments to any \fIex\fP command shall be replaced by +the current pathname; unescaped \fB'#'\fP characters shall be replaced +by the alternate pathname. It shall be an error if +\fB'%'\fP or \fB'#'\fP characters appear unescaped in an argument +and their corresponding values are not set. +.LP +Non-backslash-escaped \fB'!'\fP characters in the arguments to either +the \fIex\fP \fB!\fP command or the open and visual +mode \fB!\fP command, or in the arguments to the \fIex\fP \fBread\fP +command, where the first non- <blank> after the +command name is a \fB'!'\fP character, or in the arguments to the +\fIex\fP \fBwrite\fP command where the command name is +followed by one or more <blank>s and the first non- <blank> after +the command name is a \fB'!'\fP character, shall +be replaced with the arguments to the last of those three commands +as they appeared after all unescaped \fB'%'\fP, \fB'#'\fP, +and \fB'!'\fP characters were replaced. It shall be an error if +\fB'!'\fP characters appear unescaped in one of these +commands and there has been no previous execution of one of these +commands. +.LP +If an error occurs during the parsing or execution of an \fIex\fP +command: +.IP " *" 3 +An informational message to this effect shall be written. Execution +of the \fIex\fP command shall stop, and the cursor (for +example, the current line and column) shall not be further modified. +.LP +.IP " *" 3 +If the \fIex\fP command resulted from a map expansion, all characters +from that map expansion shall be discarded, except as +otherwise specified by the \fBmap\fP command. +.LP +.IP " *" 3 +Otherwise, if the \fIex\fP command resulted from the processing of +an \fIEXINIT\fP environment variable, a \fB.exrc\fP file, +a \fB:source\fP command, a \fB-c\fP option, or a \fB+\fP \fIcommand\fP +specified to an \fIex\fP \fBedit\fP, \fBex\fP, +\fBnext\fP, or \fBvisual\fP command, no further commands from the +source of the commands shall be executed. +.LP +.IP " *" 3 +Otherwise, if the \fIex\fP command resulted from the execution of +a buffer or a \fBglobal\fP or \fBv\fP command, no further +commands caused by the execution of the buffer or the \fBglobal\fP +or \fBv\fP command shall be executed. +.LP +.IP " *" 3 +Otherwise, if the \fIex\fP command was not terminated by a <newline>, +all characters up to and including the next +non-backslash-escaped <newline> shall be discarded. +.LP +.SS Input Editing in ex +.LP +The following symbol is used in this and the following sections to +specify command actions: +.TP 7 +\fIword\fP +In the POSIX locale, a word consists of a maximal sequence of letters, +digits, and underscores, delimited at both ends by +characters other than letters, digits, or underscores, or by the beginning +or end of a line or the edit buffer. +.sp +.LP +When accepting input characters from the user, in either \fIex\fP +command mode or \fIex\fP text input mode, \fIex\fP shall +enable canonical mode input processing, as defined in the System Interfaces +volume of IEEE\ Std\ 1003.1-2001. +.LP +If in \fIex\fP text input mode: +.IP " 1." 4 +If the \fBnumber\fP edit option is set, \fIex\fP shall prompt for +input using the line number that would be assigned to the +line if it is entered, in the format specified for the \fIex\fP \fBnumber\fP +command. +.LP +.IP " 2." 4 +If the \fBautoindent\fP edit option is set, \fIex\fP shall prompt +for input using \fBautoindent\fP characters, as described +by the \fBautoindent\fP edit option. \fBautoindent\fP characters shall +follow the line number, if any. +.LP +.LP +If in \fIex\fP command mode: +.IP " 1." 4 +If the \fBprompt\fP edit option is set, input shall be prompted for +using a single \fB':'\fP character; otherwise, there +shall be no prompt. +.LP +.LP +The input characters in the following sections shall have the following +effects on the input line. +.SS Scroll +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBeof +\fP +.fi +.RE +.sp +.LP +See the description of the \fIstty\fP \fIeof\fP character in \fIstty\fP +\&. +.LP +If in \fIex\fP command mode: +If the \fIeof\fP character is the first character entered on the line, +the line shall be evaluated as if it contained +two characters: a <control>-D and a <newline>. +.LP +Otherwise, the \fIeof\fP character shall have no special meaning. +.sp +.LP +If in \fIex\fP text input mode: +If the cursor follows an \fBautoindent\fP character, the \fBautoindent\fP +characters in the line shall be modified so +that a part of the next text input character will be displayed on +the first column in the line after the previous \fBshiftwidth\fP +edit option column boundary, and the user shall be prompted again +for input for the same line. +.LP +Otherwise, if the cursor follows a \fB'0'\fP, which follows an \fBautoindent\fP +character, and the \fB'0'\fP was the +previous text input character, the \fB'0'\fP and all \fBautoindent\fP +characters in the line shall be discarded, and the user +shall be prompted again for input for the same line. +.LP +Otherwise, if the cursor follows a \fB'^'\fP, which follows an \fBautoindent\fP +character, and the \fB'^'\fP was the +previous text input character, the \fB'^'\fP and all \fBautoindent\fP +characters in the line shall be discarded, and the user +shall be prompted again for input for the same line. In addition, +the \fBautoindent\fP level for the next input line shall be +derived from the same line from which the \fBautoindent\fP level for +the current input line was derived. +.LP +Otherwise, if there are no \fBautoindent\fP or text input characters +in the line, the \fIeof\fP character shall be +discarded. +.LP +Otherwise, the \fIeof\fP character shall have no special meaning. +.SS <newline> +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB<newline> +.sp + +<control>-J +\fP +.fi +.RE +.sp +.LP +If in \fIex\fP command mode: +Cause the command line to be parsed; <control>-J shall be mapped to +the <newline> for this +purpose. +.LP +If in \fIex\fP text input mode: +Terminate the current line. If there are no characters other than +\fBautoindent\fP characters on the line, all +characters on the line shall be discarded. +.LP +Prompt for text input on a new line after the current line. If the +\fBautoindent\fP edit option is set, an appropriate number +of \fBautoindent\fP characters shall be added as a prefix to the line +as described by the \fIex\fP \fBautoindent\fP edit +option. +.SS <backslash> +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB<backslash> +\fP +.fi +.RE +.sp +.LP +Allow the entry of a subsequent <newline> or <control>-J as a literal +character, removing any special meaning that +it may have to the editor during text input mode. The backslash character +shall be retained and evaluated when the command line is +parsed, or retained and included when the input text becomes part +of the edit buffer. +.SS <control>-V +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB<control>-V +\fP +.fi +.RE +.sp +.LP +Allow the entry of any subsequent character as a literal character, +removing any special meaning that it may have to the editor +during text input mode. The <control>-V character shall be discarded +before the command line is parsed or the input text +becomes part of the edit buffer. +.LP +If the "literal next" functionality is performed by the underlying +system, it is implementation-defined whether a character +other than <control>-V performs this function. +.SS <control>-W +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB<control>-W +\fP +.fi +.RE +.sp +.LP +Discard the <control>-W, and the word previous to it in the input +line, including any <blank>s following the word +and preceding the <control>-W. If the "word erase" functionality is +performed by the underlying system, it is +implementation-defined whether a character other than <control>-W +performs this function. +.SS Command Descriptions in ex +.LP +The following symbols are used in this section to represent command +modifiers. Some of these modifiers can be omitted, in which +case the specified defaults shall be used. +.TP 7 +\fI1addr\fP +A single line address, given in any of the forms described in Addressing +in ex ; the default +shall be the current line ( \fB'.'\fP ), unless otherwise specified. +.LP +If the line address is zero, it shall be an error, unless otherwise +specified in the following command descriptions. +.LP +If the edit buffer is empty, and the address is specified with a command +other than \fB=\fP, \fBappend\fP, \fBinsert\fP, +\fBopen\fP, \fBput\fP, \fBread\fP, or \fBvisual\fP, or the address +is not zero, it shall be an error. +.TP 7 +\fI2addr\fP +Two addresses specifying an inclusive range of lines. If no addresses +are specified, the default for \fI2addr\fP shall be the +current line only ( \fB".,."\fP ), unless otherwise specified in the +following command descriptions. If one address is +specified, \fI2addr\fP shall specify that line only, unless otherwise +specified in the following command descriptions. +.LP +It shall be an error if the first address is greater than the second +address. +.LP +If the edit buffer is empty, and the two addresses are specified with +a command other than the \fB!\fP, \fBwrite\fP, +\fBwq\fP, or \fBxit\fP commands, or either address is not zero, it +shall be an error. +.TP 7 +\fIcount\fP +A positive decimal number. If \fIcount\fP is specified, it shall be +equivalent to specifying an additional address to the +command, unless otherwise specified by the following command descriptions. +The additional address shall be equal to the last +address specified to the command (either explicitly or by default) +plus \fIcount\fP-1. +.LP +If this would result in an address greater than the last line of the +edit buffer, it shall be corrected to equal the last line +of the edit buffer. +.TP 7 +\fIflags\fP +One or more of the characters \fB'+'\fP, \fB'-'\fP, \fB'#'\fP, +\fB'p'\fP, or \fB'l'\fP (ell). The flag +characters can be <blank>-separated, and in any order or combination. +The characters \fB'#'\fP, \fB'p'\fP, and +\fB'l'\fP shall cause lines to be written in the format specified +by the \fBprint\fP command with the specified \fIflags\fP. +.LP +The lines to be written are as follows: +.RS +.IP " 1." 4 +All edit buffer lines written during the execution of the \fIex\fP +\fB&\fP, \fB~\fP, \fBlist\fP, \fBnumber\fP, +\fBopen\fP, \fBprint\fP, \fBs\fP, \fBvisual\fP, and \fBz\fP commands +shall be written as specified by \fIflags\fP. +.LP +.IP " 2." 4 +After the completion of an \fIex\fP command with a flag as an argument, +the current line shall be written as specified by +\fIflags\fP, unless the current line was the last line written by +the command. +.LP +.RE +.LP +The characters \fB'+'\fP and \fB'-'\fP cause the value of the current +line after the execution of the \fIex\fP command to +be adjusted by the offset address as described in Addressing in ex +\&. This adjustment shall occur +before the current line is written as described in 2. above. +.LP +The default for \fIflags\fP shall be none. +.TP 7 +\fIbuffer\fP +One of a number of named areas for holding text. The named buffers +are specified by the alphanumeric characters of the POSIX +locale. There shall also be one "unnamed" buffer. When no buffer is +specified for editor commands that use a buffer, the unnamed +buffer shall be used. Commands that store text into buffers shall +store the text as it was before the command took effect, and +shall store text occurring earlier in the file before text occurring +later in the file, regardless of how the text region was +specified. Commands that store text into buffers shall store the text +into the unnamed buffer as well as any specified buffer. +.LP +In \fIex\fP commands, buffer names are specified as the name by itself. +In open or visual mode commands the name is preceded by +a double quote ( \fB' )'\fP character. +.LP +If the specified buffer name is an uppercase character, and the buffer +contents are to be modified, the buffer shall be appended +to rather than being overwritten. If the buffer is not being modified, +specifying the buffer name in lowercase and uppercase shall +have identical results. +.LP +There shall also be buffers named by the numbers 1 through 9. In open +and visual mode, if a region of text including characters +from more than a single line is being modified by the \fIvi\fP \fBc\fP +or \fBd\fP commands, +the motion character associated with the \fBc\fP or \fBd\fP commands +specifies that the buffer text shall be in line mode, or the +commands \fB%\fP, \fB`\fP, \fB/\fP, \fB?\fP, \fB(\fP, \fB)\fP, \fBN\fP, +\fBn\fP, \fB{\fP, or \fB}\fP are used to define a +region of text for the \fBc\fP or \fBd\fP commands, the contents of +buffers 1 through 8 shall be moved into the buffer named by +the next numerically greater value, the contents of buffer 9 shall +be discarded, and the region of text shall be copied into buffer +1. This shall be in addition to copying the text into a user-specified +buffer or unnamed buffer, or both. Numeric buffers can be +specified as a source buffer for open and visual mode commands; however, +specifying a numeric buffer as the write target of an open +or visual mode command shall have unspecified results. +.LP +The text of each buffer shall have the characteristic of being in +either line or character mode. Appending text to a non-empty +buffer shall set the mode to match the characteristic of the text +being appended. Appending text to a buffer shall cause the +creation of at least one additional line in the buffer. All text stored +into buffers by \fIex\fP commands shall be in line mode. +The \fIex\fP commands that use buffers as the source of text specify +individually how buffers of different modes are handled. Each +open or visual mode command that uses buffers for any purpose specifies +individually the mode of the text stored into the buffer +and how buffers of different modes are handled. +.TP 7 +\fIfile\fP +Command text used to derive a pathname. The default shall be the current +pathname, as defined previously, in which case, if no +current pathname has yet been established it shall be an error, except +where specifically noted in the individual command +descriptions that follow. If the command text contains any of the +characters \fB'~'\fP, \fB'{'\fP, \fB'['\fP, +\fB'*'\fP, \fB'?'\fP, \fB'$'\fP, \fB'`'\fP, \fB'"\fP, \fB' ,'\fP +and \fB'\\'\fP, it shall be subjected +to the process of "shell expansions", as described below; if more +than a single pathname results and the command expects only +one, it shall be an error. +.LP +The process of shell expansions in the editor shall be done as follows. +The \fIex\fP utility shall pass two arguments to the +program named by the shell edit option; the first shall be \fB-c\fP, +and the second shall be the string \fB"echo"\fP and the +command text as a single argument. The standard output and standard +error of that command shall replace the command text. +.TP 7 +\fB!\fP +A character that can be appended to the command name to modify its +operation, as detailed in the individual command +descriptions. With the exception of the \fIex\fP \fBread\fP, \fBwrite\fP, +and \fB!\fP commands, the \fB'!'\fP character +shall only act as a modifier if there are no <blank>s between it and +the command name. +.TP 7 +\fIremembered\ search\ direction\fP +.sp +The \fIvi\fP commands \fBN\fP and \fBn\fP begin searching in a forwards +or backwards +direction in the edit buffer based on a remembered search direction, +which is initially unset, and is set by the \fIex\fP +\fBglobal\fP, \fBv\fP, \fBs\fP, and \fBtag\fP commands, and the \fIvi\fP +\fB/\fP and +\fB?\fP commands. +.sp +.SS Abbreviate +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBab\fP\fB[\fP\fIbreviate\fP\fB][\fP\fIlhs rhs\fP\fB]\fP +.fi +.RE +.sp +.LP +If \fIlhs\fP and \fIrhs\fP are not specified, write the current list +of abbreviations and do nothing more. +.LP +Implementations may restrict the set of characters accepted in \fIlhs\fP +or \fIrh\fP, except that printable characters and +<blank>s shall not be restricted. Additional restrictions shall be +implementation-defined. +.LP +In both \fIlhs\fP and \fIrhs\fP, any character may be escaped with +a <control>-V, in which case the character shall not +be used to delimit \fIlhs\fP from \fIrhs\fP, and the escaping <control>-V +shall be discarded. +.LP +In open and visual text input mode, if a non-word or <ESC> character +that is not escaped by a <control>-V character +is entered after a word character, a check shall be made for a set +of characters matching \fIlhs\fP, in the text input entered +during this command. If it is found, the effect shall be as if \fIrhs\fP +was entered instead of \fIlhs\fP. +.LP +The set of characters that are checked is defined as follows: +.IP " 1." 4 +If there are no characters inserted before the word and non-word or +<ESC> characters that triggered the check, the set of +characters shall consist of the word character. +.LP +.IP " 2." 4 +If the character inserted before the word and non-word or <ESC> characters +that triggered the check is a word character, +the set of characters shall consist of the characters inserted immediately +before the triggering characters that are word +characters, plus the triggering word character. +.LP +.IP " 3." 4 +If the character inserted before the word and non-word or <ESC> characters +that triggered the check is not a word +character, the set of characters shall consist of the characters that +were inserted before the triggering characters that are +neither <blank>s nor word characters, plus the triggering word character. +.LP +.LP +It is unspecified whether the \fIlhs\fP argument entered for the \fIex\fP +\fBabbreviate\fP and \fBunabbreviate\fP commands +is replaced in this fashion. Regardless of whether or not the replacement +occurs, the effect of the command shall be as if the +replacement had not occurred. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Append +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBa\fP\fB[\fP\fBppend\fP\fB][\fP\fB!\fP\fB]\fP +.fi +.RE +.sp +.LP +Enter \fIex\fP text input mode; the input text shall be placed after +the specified line. If line zero is specified, the text +shall be placed at the beginning of the edit buffer. +.LP +This command shall be affected by the \fBnumber\fP and \fBautoindent\fP +edit options; following the command name with +\fB'!'\fP shall cause the \fBautoindent\fP edit option setting to +be toggled for the duration of this command only. +.LP +\fICurrent line\fP: Set to the last input line; if no lines were input, +set to the specified line, or to the first line of the +edit buffer if a line of zero was specified, or zero if the edit buffer +is empty. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Arguments +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBar\fP\fB[\fP\fIgs\fP\fB]\fP +.fi +.RE +.sp +.LP +Write the current argument list, with the current argument-list entry, +if any, between \fB'['\fP and \fB']'\fP +characters. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Change +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBc\fP\fB[\fP\fBhange\fP\fB][\fP\fB!\fP\fB][\fP\fIcount\fP\fB]\fP +.fi +.RE +.sp +.LP +Enter \fIex\fP text input mode; the input text shall replace the specified +lines. The specified lines shall be copied into the +unnamed buffer, which shall become a line mode buffer. +.LP +This command shall be affected by the \fBnumber\fP and \fBautoindent\fP +edit options; following the command name with +\fB'!'\fP shall cause the \fBautoindent\fP edit option setting to +be toggled for the duration of this command only. +.LP +\fICurrent line\fP: Set to the last input line; if no lines were input, +set to the line before the first address, or to the +first line of the edit buffer if there are no lines preceding the +first address, or to zero if the edit buffer is empty. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Change Directory +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBchd\fP\fB[\fP\fBir\fP\fB][\fP\fB!\fP\fB][\fP\fIdirectory\fP\fB]\fP\fBcd\fP\fB[\fP\fB!\fP\fB][\fP\fIdirectory\fP\fB]\fP +.fi +.RE +.sp +.LP +Change the current working directory to \fIdirectory\fP. +.LP +If no \fIdirectory\fP argument is specified, and the \fIHOME\fP environment +variable is set to a non-null and non-empty value, +\fIdirectory\fP shall default to the value named in the \fIHOME\fP +environment variable. If the \fIHOME\fP environment variable +is empty or is undefined, the default value of \fIdirectory\fP is +implementation-defined. +.LP +If no \fB'!'\fP is appended to the command name, and the edit buffer +has been modified since the last complete write, and the +current pathname does not begin with a \fB'/'\fP, it shall be an +error. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Copy +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBco\fP\fB[\fP\fBpy\fP\fB]\fP \fI1addr\fP \fB[\fP\fIflags\fP\fB] +[\fP\fI2addr\fP\fB]\fP \fBt\fP \fI1addr\fP \fB[\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +Copy the specified lines after the specified destination line; line +zero specifies that the lines shall be placed at the +beginning of the edit buffer. +.LP +\fICurrent line\fP: Set to the last line copied. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Delete +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBd\fP\fB[\fP\fBelete\fP\fB][\fP\fIbuffer\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +Delete the specified lines into a buffer (defaulting to the unnamed +buffer), which shall become a line-mode buffer. +.LP +Flags can immediately follow the command name; see Command Line Parsing +in ex . +.LP +\fICurrent line\fP: Set to the line following the deleted lines, or +to the last line in the edit buffer if that line is past +the end of the edit buffer, or to zero if the edit buffer is empty. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Edit +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBe\fP\fB[\fP\fBdit\fP\fB][\fP\fB!\fP\fB][\fP\fB+\fP\fIcommand\fP\fB][\fP\fIfile\fP\fB]\fP\fBex\fP\fB[\fP\fB!\fP\fB][\fP\fB+\fP\fIcommand\fP\fB][\fP\fIfile\fP\fB]\fP +.fi +.RE +.sp +.LP +If no \fB'!'\fP is appended to the command name, and the edit buffer +has been modified since the last complete write, it +shall be an error. +.LP +If \fIfile\fP is specified, replace the current contents of the edit +buffer with the current contents of \fIfile\fP, and set +the current pathname to \fIfile\fP. If \fIfile\fP is not specified, +replace the current contents of the edit buffer with the +current contents of the file named by the current pathname. If for +any reason the current contents of the file cannot be accessed, +the edit buffer shall be empty. +.LP +The \fB+\fP \fIcommand\fP option shall be <blank>-delimited; <blank>s +within \fB+\fP \fIcommand\fP can be +escaped by preceding them with a backslash character. The \fB+\fP +\fIcommand\fP shall be interpreted as an \fIex\fP command +immediately after the contents of the edit buffer have been replaced +and the current line and column have been set. +.LP +If the edit buffer is empty: +.LP +\fICurrent line\fP: Set to 0. +.LP +\fICurrent column\fP: Set to 1. +.LP +Otherwise, if executed while in \fIex\fP command mode or if the \fB+\fP +\fIcommand\fP argument is specified: +.LP +\fICurrent line\fP: Set to the last line of the edit buffer. +.LP +\fICurrent column\fP: Set to non- <blank>. +.LP +Otherwise, if \fIfile\fP is omitted or results in the current pathname: +.LP +\fICurrent line\fP: Set to the first line of the edit buffer. +.LP +\fICurrent column\fP: Set to non- <blank>. +.LP +Otherwise, if \fIfile\fP is the same as the last file edited, the +line and column shall be set as follows; if the file was +previously edited, the line and column may be set as follows: +.LP +\fICurrent line\fP: Set to the last value held when that file was +last edited. If this value is not a valid line in the new +edit buffer, set to the first line of the edit buffer. +.LP +\fICurrent column\fP: If the current line was set to the last value +held when the file was last edited, set to the last value +held when the file was last edited. Otherwise, or if the last value +is not a valid column in the new edit buffer, set to non- +<blank>. +.LP +Otherwise: +.LP +\fICurrent line\fP: Set to the first line of the edit buffer. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS File +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBf\fP\fB[\fP\fBile\fP\fB][\fP\fIfile\fP\fB]\fP +.fi +.RE +.sp +.LP +If a \fIfile\fP argument is specified, the alternate pathname shall +be set to the current pathname, and the current pathname +shall be set to \fIfile\fP. +.LP +Write an informational message. If the file has a current pathname, +it shall be included in this message; otherwise, the message +shall indicate that there is no current pathname. If the edit buffer +contains lines, the current line number and the number of +lines in the edit buffer shall be included in this message; otherwise, +the message shall indicate that the edit buffer is empty. If +the edit buffer has been modified since the last complete write, this +fact shall be included in this message. If the +\fBreadonly\fP edit option is set, this fact shall be included in +this message. The message may contain other unspecified +information. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Global +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBg\fP\fB[\fP\fBlobal\fP\fB]\fP \fB/\fP\fIpattern\fP\fB/\fP \fB[\fP\fIcommands\fP\fB] +[\fP\fI2addr\fP\fB]\fP \fBv /\fP\fIpattern\fP\fB/\fP \fB[\fP\fIcommands\fP\fB]\fP +.fi +.RE +.sp +.LP +The optional \fB'!'\fP character after the \fBglobal\fP command shall +be the same as executing the \fBv\fP command. +.LP +If \fIpattern\fP is empty (for example, \fB"//"\fP ) or not specified, +the last regular expression used in the editor +command shall be used as the \fIpattern\fP. The \fIpattern\fP can +be delimited by slashes (shown in the Synopsis), as well as any +non-alphanumeric or non- <blank> other than backslash, vertical line, +double quote, or <newline>. +.LP +If no lines are specified, the lines shall default to the entire file. +.LP +The \fBglobal\fP and \fBv\fP commands are logically two-pass operations. +First, mark the lines within the specified lines for +which the line excluding the terminating <newline> matches ( \fBglobal\fP) +or does not match ( \fBv\fP or \fBglobal!\fP) +the specified pattern. Second, execute the \fIex\fP commands given +by \fIcommands\fP, with the current line ( \fB'.'\fP ) set +to each marked line. If an error occurs during this process, or the +contents of the edit buffer are replaced (for example, by the +\fIex\fP \fB:edit\fP command) an error message shall be written and +no more commands resulting from the execution of this command +shall be processed. +.LP +Multiple \fIex\fP commands can be specified by entering multiple commands +on a single line using a vertical line to delimit +them, or one per line, by escaping each <newline> with a backslash. +.LP +If no commands are specified: +.IP " 1." 4 +If in \fIex\fP command mode, it shall be as if the \fBprint\fP command +were specified. +.LP +.IP " 2." 4 +Otherwise, no command shall be executed. +.LP +.LP +For the \fBappend\fP, \fBchange\fP, and \fBinsert\fP commands, the +input text shall be included as part of the command, and +the terminating period can be omitted if the command ends the list +of commands. The \fBopen\fP and \fBvisual\fP commands can be +specified as one of the commands, in which case each marked line shall +cause the editor to enter open or visual mode. If open or +visual mode is exited using the \fIvi\fP \fBQ\fP command, the current +line shall be set to the +next marked line, and open or visual mode reentered, until the list +of marked lines is exhausted. +.LP +The \fBglobal\fP, \fBv\fP, and \fBundo\fP commands cannot be used +in \fIcommands\fP. Marked lines may be deleted by commands +executed for lines occurring earlier in the file than the marked lines. +In this case, no commands shall be executed for the deleted +lines. +.LP +If the remembered search direction is not set, the \fBglobal\fP and +\fBv\fP commands shall set it to forward. +.LP +The \fBautoprint\fP and \fBautoindent\fP edit options shall be inhibited +for the duration of the \fBg\fP or \fBv\fP +command. +.LP +\fICurrent line\fP: If no commands executed, set to the last marked +line. Otherwise, as specified for the executed \fIex\fP +commands. +.LP +\fICurrent column\fP: If no commands are executed, set to non- <blank>; +otherwise, as specified for the individual +\fIex\fP commands. +.SS Insert +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBi\fP\fB[\fP\fBnsert\fP\fB][\fP\fB!\fP\fB]\fP +.fi +.RE +.sp +.LP +Enter \fIex\fP text input mode; the input text shall be placed before +the specified line. If the line is zero or 1, the text +shall be placed at the beginning of the edit buffer. +.LP +This command shall be affected by the \fBnumber\fP and \fBautoindent\fP +edit options; following the command name with +\fB'!'\fP shall cause the \fBautoindent\fP edit option setting to +be toggled for the duration of this command only. +.LP +\fICurrent line\fP: Set to the last input line; if no lines were input, +set to the line before the specified line, or to the +first line of the edit buffer if there are no lines preceding the +specified line, or zero if the edit buffer is empty. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Join +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBj\fP\fB[\fP\fBoin\fP\fB][\fP\fB!\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +If \fIcount\fP is specified: +If no address was specified, the \fBjoin\fP command shall behave as +if \fI2addr\fP were the current line and the +current line plus \fIcount\fP (.,. + \fIcount\fP). +.LP +If one address was specified, the \fBjoin\fP command shall behave +as if \fI2addr\fP were the specified address and the +specified address plus \fIcount\fP ( \fIaddr\fP, \fIaddr\fP + \fIcount\fP). +.LP +If two addresses were specified, the \fBjoin\fP command shall behave +as if an additional address, equal to the last address +plus \fIcount\fP -1 ( \fIaddr1\fP, \fIaddr2\fP, \fIaddr2\fP + \fIcount\fP +-1), was specified. +.LP +If this would result in a second address greater than the last line +of the edit buffer, it shall be corrected to be equal to the +last line of the edit buffer. +.LP +If no \fIcount\fP is specified: +If no address was specified, the \fBjoin\fP command shall behave as +if \fI2addr\fP were the current line and the next +line (.,. +1). +.LP +If one address was specified, the \fBjoin\fP command shall behave +as if \fI2addr\fP were the specified address and the next +line ( \fIaddr\fP, \fIaddr\fP +1). +.LP +Join the text from the specified lines together into a single line, +which shall replace the specified lines. +.LP +If a \fB'!'\fP character is appended to the command name, the \fBjoin\fP +shall be without modification of any line, +independent of the current locale. +.LP +Otherwise, in the POSIX locale, set the current line to the first +of the specified lines, and then, for each subsequent line, +proceed as follows: +.IP " 1." 4 +Discard leading <space>s from the line to be joined. +.LP +.IP " 2." 4 +If the line to be joined is now empty, delete it, and skip steps 3 +through 5. +.LP +.IP " 3." 4 +If the current line ends in a <blank>, or the first character of the +line to be joined is a \fB')'\fP character, join +the lines without further modification. +.LP +.IP " 4." 4 +If the last character of the current line is a \fB'.'\fP, join the +lines with two <space>s between them. +.LP +.IP " 5." 4 +Otherwise, join the lines with a single <space> between them. +.LP +.LP +\fICurrent line\fP: Set to the first line specified. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS List +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBl\fP\fB[\fP\fBist\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +This command shall be equivalent to the \fIex\fP command: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBp\fP\fB[\fP\fBrint\fP\fB][\fP\fIcount\fP\fB]\fP \fBl\fP\fB[\fP\fIflags\fP\fB]\fP +.fi +.RE +.LP +See Print . +.SS Map +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBmap\fP\fB[\fP\fB!\fP\fB][\fP\fIlhs rhs\fP\fB]\fP +.fi +.RE +.sp +.LP +If \fIlhs\fP and \fIrhs\fP are not specified: +.IP " 1." 4 +If \fB'!'\fP is specified, write the current list of text input mode +maps. +.LP +.IP " 2." 4 +Otherwise, write the current list of command mode maps. +.LP +.IP " 3." 4 +Do nothing more. +.LP +.LP +Implementations may restrict the set of characters accepted in \fIlhs\fP +or \fIrhs\fP, except that printable characters and +<blank>s shall not be restricted. Additional restrictions shall be +implementation-defined. In both \fIlhs\fP and \fIrhs\fP, +any character can be escaped with a <control>-V, in which case the +character shall not be used to delimit \fIlhs\fP from +\fIrhs\fP, and the escaping <control>-V shall be discarded. +.LP +If the character \fB'!'\fP is appended to the \fBmap\fP command name, +the mapping shall be effective during open or visual +text input mode rather than \fBopen\fP or \fBvisual\fP command mode. +This allows \fIlhs\fP to have two different \fBmap\fP +definitions at the same time: one for command mode and one for text +input mode. +.LP +For command mode mappings: +When the \fIlhs\fP is entered as any part of a \fIvi\fP command in +open or visual +mode (but not as part of the arguments to the command), the action +shall be as if the corresponding \fIrhs\fP had been entered. +.LP +If any character in the command, other than the first, is escaped +using a <control>-V character, that character shall not +be part of a match to an \fIlhs\fP. +.LP +It is unspecified whether implementations shall support \fBmap\fP +commands where the \fIlhs\fP is more than a single character +in length, where the first character of the \fIlhs\fP is printable. +.LP +If \fIlhs\fP contains more than one character and the first character +is \fB'#'\fP, followed by a sequence of digits +corresponding to a numbered function key, then when this function +key is typed it shall be mapped to \fIrhs\fP. Characters other +than digits following a \fB'#'\fP character also represent the function +key named by the characters in the \fIlhs\fP following +the \fB'#'\fP and may be mapped to \fIrhs\fP. It is unspecified how +function keys are named or what function keys are +supported. +.LP +For text input mode mappings: +When the \fIlhs\fP is entered as any part of text entered in open +or visual text input modes, the action shall be as +if the corresponding \fIrhs\fP had been entered. +.LP +If any character in the input text is escaped using a <control>-V +character, that character shall not be part of a match +to an \fIlhs\fP. +.LP +It is unspecified whether the \fIlhs\fP text entered for subsequent +\fBmap\fP or \fBunmap\fP commands is replaced with the +\fIrhs\fP text for the purposes of the screen display; regardless +of whether or not the display appears as if the corresponding +\fIrhs\fP text was entered, the effect of the command shall be as +if the \fIlhs\fP text was entered. +.LP +If only part of the \fIlhs\fP is entered, it is unspecified how long +the editor will wait for additional, possibly matching +characters before treating the already entered characters as not matching +the \fIlhs\fP. +.LP +The \fIrhs\fP characters shall themselves be subject to remapping, +unless otherwise specified by the \fBremap\fP edit option, +except that if the characters in \fIlhs\fP occur as prefix characters +in \fIrhs\fP, those characters shall not be remapped. +.LP +On block-mode terminals, the mapping need not occur immediately (for +example, it may occur after the terminal transmits a group +of characters to the system), but it shall achieve the same results +as if it occurred immediately. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Mark +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBma\fP\fB[\fP\fBrk\fP\fB]\fP \fIcharacter +\fP\fB[\fP\fI1addr\fP\fB]\fP \fBk\fP \fIcharacter\fP +.fi +.RE +.sp +.LP +Implementations shall support \fIcharacter\fP values of a single lowercase +letter of the POSIX locale and the characters +\fB'`'\fP and \fB'"\fP ; support of other characters is implementation-defined. +.LP +If executing the \fIvi\fP \fBm\fP command, set the specified mark +to the current line and +1-based numbered character referenced by the current column, if any; +otherwise, column position 1. +.LP +Otherwise, set the specified mark to the specified line and 1-based +numbered first non- <blank> non- <newline> in +the line, if any; otherwise, the last non- <newline> in the line, +if any; otherwise, column position 1. +.LP +The mark shall remain associated with the line until the mark is reset +or the line is deleted. If a deleted line is restored by +a subsequent \fBundo\fP command, any marks previously associated with +the line, which have not been reset, shall be restored as +well. Any use of a mark not associated with a current line in the +edit buffer shall be an error. +.LP +The marks \fB`\fP and \fB'\fP shall be set as described previously, +immediately before the following events occur in the +editor: +.IP " 1." 4 +The use of \fB'$'\fP as an \fIex\fP address +.LP +.IP " 2." 4 +The use of a positive decimal number as an \fIex\fP address +.LP +.IP " 3." 4 +The use of a search command as an \fIex\fP address +.LP +.IP " 4." 4 +The use of a mark reference as an \fIex\fP address +.LP +.IP " 5." 4 +The use of the following open and visual mode commands: <control>-], +\fB%\fP, \fB(\fP, \fB)\fP, \fB[\fP, \fB]\fP, +\fB{\fP, \fB}\fP +.LP +.IP " 6." 4 +The use of the following open and visual mode commands: \fB'\fP, \fBG\fP, +\fBH\fP, \fBL\fP, \fBM\fP, \fBz\fP if the +current line will change as a result of the command +.LP +.IP " 7." 4 +The use of the open and visual mode commands: \fB/\fP, \fB?\fP, \fBN\fP, +\fB`\fP, \fBn\fP if the current line or column +will change as a result of the command +.LP +.IP " 8." 4 +The use of the \fIex\fP mode commands: \fBz\fP, \fBundo\fP, \fBglobal\fP, +\fBv\fP +.LP +.LP +For rules 1., 2., 3., and 4., the \fB`\fP and \fB'\fP marks shall +not be set if the \fIex\fP command is parsed as specified +by rule 6.a. in Command Line Parsing in ex . +.LP +For rules 5., 6., and 7., the \fB`\fP and \fB'\fP marks shall not +be set if the commands are used as motion commands in open +and visual mode. +.LP +For rules 1., 2., 3., 4., 5., 6., 7., and 8., the \fB`\fP and \fB'\fP +marks shall not be set if the command fails. +.LP +The \fB`\fP and \fB'\fP marks shall be set as described previously, +each time the contents of the edit buffer are replaced +(including the editing of the initial buffer), if in open or visual +mode, or if in \fBex\fP mode and the edit buffer is not empty, +before any commands or movements (including commands or movements +specified by the \fB-c\fP or \fB-t\fP options or the \fB+\fP +\fIcommand\fP argument) are executed on the edit buffer. If in open +or visual mode, the marks shall be set as if executing the \fIvi\fP +\fBm\fP command; otherwise, as if executing the \fIex\fP \fBmark\fP +command. +.LP +When changing from \fBex\fP mode to open or visual mode, if the \fB`\fP +and \fB'\fP marks are not already set, the \fB`\fP +and \fB'\fP marks shall be set as described previously. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Move +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBm\fP\fB[\fP\fBove\fP\fB]\fP \fI1addr\fP \fB\fP\fB[\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +Move the specified lines after the specified destination line. A destination +of line zero specifies that the lines shall be +placed at the beginning of the edit buffer. It shall be an error if +the destination line is within the range of lines to be +moved. +.LP +\fICurrent line\fP: Set to the last of the moved lines. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Next +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBn\fP\fB[\fP\fBext\fP\fB][\fP\fB!\fP\fB][\fP\fB+\fP\fIcommand\fP\fB][\fP\fIfile\fP \fB...\fP\fB]\fP +.fi +.RE +.sp +.LP +If no \fB'!'\fP is appended to the command name, and the edit buffer +has been modified since the last complete write, it +shall be an error, unless the file is successfully written as specified +by the \fBautowrite\fP option. +.LP +If one or more files is specified: +.IP " 1." 4 +Set the argument list to the specified filenames. +.LP +.IP " 2." 4 +Set the current argument list reference to be the first entry in the +argument list. +.LP +.IP " 3." 4 +Set the current pathname to the first filename specified. +.LP +.LP +Otherwise: +.IP " 1." 4 +It shall be an error if there are no more filenames in the argument +list after the filename currently referenced. +.LP +.IP " 2." 4 +Set the current pathname and the current argument list reference to +the filename after the filename currently referenced in the +argument list. +.LP +.LP +Replace the contents of the edit buffer with the contents of the file +named by the current pathname. If for any reason the +contents of the file cannot be accessed, the edit buffer shall be +empty. +.LP +This command shall be affected by the \fBautowrite\fP and \fBwriteany\fP +edit options. +.LP +The \fB+\fP \fIcommand\fP option shall be <blank>-delimited; <blank>s +can be escaped by preceding them with a +backslash character. The \fB+\fP \fIcommand\fP shall be interpreted +as an \fIex\fP command immediately after the contents of the +edit buffer have been replaced and the current line and column have +been set. +.LP +\fICurrent line\fP: Set as described for the \fBedit\fP command. +.LP +\fICurrent column\fP: Set as described for the \fBedit\fP command. +.SS Number +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBnu\fP\fB[\fP\fBmber\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB] +[\fP\fI2addr\fP\fB]\fP \fB#\fP\fB[\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +These commands shall be equivalent to the \fIex\fP command: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBp\fP\fB[\fP\fBrint\fP\fB][\fP\fIcount\fP\fB]\fP \fB#\fP\fB[\fP\fIflags\fP\fB]\fP +.fi +.RE +.LP +See Print . +.SS Open +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBo\fP\fB[\fP\fBpen\fP\fB]\fP \fB/\fP\fIpattern\fP\fB/\fP \fB[\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +This command need not be supported on block-mode terminals or terminals +with insufficient capabilities. If standard input, +standard output, or standard error are not terminal devices, the results +are unspecified. +.LP +Enter open mode. +.LP +The trailing delimiter can be omitted from \fIpattern\fP at the end +of the command line. If \fIpattern\fP is empty (for +example, \fB"//"\fP ) or not specified, the last regular expression +used in the editor shall be used as the pattern. The pattern +can be delimited by slashes (shown in the Synopsis), as well as any +alphanumeric, or non- <blank> other than backslash, +vertical line, double quote, or <newline>. +.LP +\fICurrent line\fP: Set to the specified line. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Preserve +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBpre\fP\fB[\fP\fBserve\fP\fB]\fP +.fi +.RE +.sp +.LP +Save the edit buffer in a form that can later be recovered by using +the \fB-r\fP option or by using the \fIex\fP +\fBrecover\fP command. After the file has been preserved, a mail message +shall be sent to the user. This message shall be readable +by invoking the \fImailx\fP utility. The message shall contain the +name of the file, the +time of preservation, and an \fIex\fP command that could be used to +recover the file. Additional information may be included in +the mail message. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Print +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBp\fP\fB[\fP\fBrint\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +Write the addressed lines. The behavior is unspecified if the number +of columns on the display is less than the number of +columns required to write any single character in the lines being +written. +.LP +Non-printable characters, except for the <tab>, shall be written as +implementation-defined multi-character sequences. +.LP +If the \fB#\fP flag is specified or the \fBnumber\fP edit option is +set, each line shall be preceded by its line number in the +following format: +.sp +.RS +.nf + +\fB"%6d ", <\fP\fIline number\fP\fB> +\fP +.fi +.RE +.LP +If the \fBl\fP flag is specified or the \fBlist\fP edit option is +set: +.IP " 1." 4 +The characters listed in the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +Table 5-1, Escape Sequences and +Associated Actions shall be written as the corresponding escape sequence. +.LP +.IP " 2." 4 +Non-printable characters not in the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +Table 5-1, Escape Sequences and +Associated Actions shall be written as one three-digit octal number +(with a preceding backslash) for each byte in the character +(most significant byte first). If the size of a byte on the system +is greater than 9 bits, the format used for non-printable +characters is implementation-defined. +.LP +.IP " 3." 4 +The end of each line shall be marked with a \fB'$'\fP, and literal +\fB'$'\fP characters within the line shall be written +with a preceding backslash. +.LP +.LP +Long lines shall be folded; the length at which folding occurs is +unspecified, but should be appropriate for the output +terminal, considering the number of columns of the terminal. +.LP +If a line is folded, and the \fBl\fP flag is not specified and the +\fBlist\fP edit option is not set, it is unspecified +whether a multi-column character at the folding position is separated; +it shall not be discarded. +.LP +\fICurrent line\fP: Set to the last written line. +.LP +\fICurrent column\fP: Unchanged if the current line is unchanged; +otherwise, set to non- <blank>. +.SS Put +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBpu\fP\fB[\fP\fBt\fP\fB][\fP\fIbuffer\fP\fB]\fP +.fi +.RE +.sp +.LP +Append text from the specified buffer (by default, the unnamed buffer) +to the specified line; line zero specifies that the text +shall be placed at the beginning of the edit buffer. Each portion +of a line in the buffer shall become a new line in the edit +buffer, regardless of the mode of the buffer. +.LP +\fICurrent line\fP: Set to the last line entered into the edit buffer. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Quit +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBq\fP\fB[\fP\fBuit\fP\fB][\fP\fB!\fP\fB]\fP +.fi +.RE +.sp +.LP +If no \fB'!'\fP is appended to the command name: +.IP " 1." 4 +If the edit buffer has been modified since the last complete write, +it shall be an error. +.LP +.IP " 2." 4 +If there are filenames in the argument list after the filename currently +referenced, and the last command was not a \fBquit\fP, +\fBwq\fP, \fBxit\fP, or \fBZZ\fP (see \fIExit\fP ) command, it shall +be an error. +.LP +.LP +Otherwise, terminate the editing session. +.SS Read +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBr\fP\fB[\fP\fBead\fP\fB][\fP\fB!\fP\fB][\fP\fIfile\fP\fB]\fP +.fi +.RE +.sp +.LP +If \fB'!'\fP is not the first non- <blank> to follow the command name, +a copy of the specified file shall be appended +into the edit buffer after the specified line; line zero specifies +that the copy shall be placed at the beginning of the edit +buffer. The number of lines and bytes read shall be written. If no +\fIfile\fP is named, the current pathname shall be the default. +If there is no current pathname, then \fIfile\fP shall become the +current pathname. If there is no current pathname or \fIfile\fP +operand, it shall be an error. Specifying a \fIfile\fP that is not +of type regular shall have unspecified results. +.LP +Otherwise, if \fIfile\fP is preceded by \fB'!'\fP, the rest of the +line after the \fB'!'\fP shall have \fB'%'\fP, +\fB'#'\fP, and \fB'!'\fP characters expanded as described in Command +Line Parsing in ex . +.LP +The \fIex\fP utility shall then pass two arguments to the program +named by the shell edit option; the first shall be \fB-c\fP +and the second shall be the expanded arguments to the \fBread\fP command +as a single argument. The standard input of the program +shall be set to the standard input of the \fIex\fP program when it +was invoked. The standard error and standard output of the +program shall be appended into the edit buffer after the specified +line. +.LP +Each line in the copied file or program output (as delimited by <newline>s +or the end of the file or output if it is not +immediately preceded by a <newline>), shall be a separate line in +the edit buffer. Any occurrences of <carriage-return> +and <newline> pairs in the output shall be treated as single <newline>s. +.LP +The special meaning of the \fB'!'\fP following the \fBread\fP command +can be overridden by escaping it with a backslash +character. +.LP +\fICurrent line\fP: If no lines are added to the edit buffer, unchanged. +Otherwise, if in open or visual mode, set to the first +line entered into the edit buffer. Otherwise, set to the last line +entered into the edit buffer. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Recover +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBrec\fP\fB[\fP\fBover\fP\fB][\fP\fB!\fP\fB]\fP \fIfile\fP +.fi +.RE +.sp +.LP +If no \fB'!'\fP is appended to the command name, and the edit buffer +has been modified since the last complete write, it +shall be an error. +.LP +If no \fIfile\fP operand is specified, then the current pathname shall +be used. If there is no current pathname or \fIfile\fP +operand, it shall be an error. +.LP +If no recovery information has previously been saved about \fIfile\fP, +the \fBrecover\fP command shall behave identically to +the \fBedit\fP command, and an informational message to this effect +shall be written. +.LP +Otherwise, set the current pathname to \fIfile\fP, and replace the +current contents of the edit buffer with the recovered +contents of \fIfile\fP. If there are multiple instances of the file +to be recovered, the one most recently saved shall be +recovered, and an informational message that there are previous versions +of the file that can be recovered shall be written. The +editor shall behave as if the contents of the edit buffer have already +been modified. +.LP +\fICurrent file\fP: Set as described for the \fBedit\fP command. +.LP +\fICurrent column\fP: Set as described for the \fBedit\fP command. +.SS Rewind +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBrew\fP\fB[\fP\fBind\fP\fB][\fP\fB!\fP\fB]\fP +.fi +.RE +.sp +.LP +If no \fB'!'\fP is appended to the command name, and the edit buffer +has been modified since the last complete write, it +shall be an error, unless the file is successfully written as specified +by the \fBautowrite\fP option. +.LP +If the argument list is empty, it shall be an error. +.LP +The current argument list reference and the current pathname shall +be set to the first filename in the argument list. +.LP +Replace the contents of the edit buffer with the contents of the file +named by the current pathname. If for any reason the +contents of the file cannot be accessed, the edit buffer shall be +empty. +.LP +This command shall be affected by the \fBautowrite\fP and \fBwriteany\fP +edit options. +.LP +\fICurrent line\fP: Set as described for the \fBedit\fP command. +.LP +\fICurrent column\fP: Set as described for the \fBedit\fP command. +.SS Set +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBse\fP\fB[\fP\fBt\fP\fB][\fP\fIoption\fP\fB[\fP\fB=\fP\fB[\fP\fIvalue\fP\fB]]\fP \fB...\fP\fB][\fP\fBno\fP\fIoption\fP \fB...\fP\fB][\fP\fIoption\fP\fB? ...\fP\fB][\fP\fBall\fP\fB]\fP +.fi +.RE +.sp +.LP +When no arguments are specified, write the value of the \fBterm\fP +edit option and those options whose values have been changed +from the default settings; when the argument \fIall\fP is specified, +write all of the option values. +.LP +Giving an option name followed by the character \fB'?'\fP shall cause +the current value of that option to be written. The +\fB'?'\fP can be separated from the option name by zero or more <blank>s. +The \fB'?'\fP shall be necessary only for +Boolean valued options. Boolean options can be given values by the +form \fBset\fP \fIoption\fP to turn them on or \fBset\fP +\fBno\fP \fIoption\fP to turn them off; string and numeric options +can be assigned by the form \fBset\fP \fIoption\fP= +\fIvalue\fP. Any <blank>s in strings can be included as is by preceding +each <blank> with an escaping backslash. More +than one option can be set or listed by a single set command by specifying +multiple arguments, each separated from the next by one +or more <blank>s. +.LP +See Edit Options in ex for details about specific options. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Shell +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBsh\fP\fB[\fP\fBell\fP\fB]\fP +.fi +.RE +.sp +.LP +Invoke the program named in the \fBshell\fP edit option with the single +argument \fB-i\fP (interactive mode). Editing shall be +resumed when the program exits. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Source +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBso\fP\fB[\fP\fBurce\fP\fB]\fP \fIfile\fP +.fi +.RE +.sp +.LP +Read and execute \fIex\fP commands from \fIfile\fP. Lines in the file +that are blank lines shall be ignored. +.LP +\fICurrent line\fP: As specified for the individual \fIex\fP commands. +.LP +\fICurrent column\fP: As specified for the individual \fIex\fP commands. +.SS Substitute +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBs\fP\fB[\fP\fBubstitute\fP\fB][\fP\fB/\fP\fIpattern\fP\fB/\fP\fIrepl\fP\fB/\fP\fB[\fP\fIoptions\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]]\fP\fB +.br + +\fP\fB[\fP\fI2addr\fP\fB]\fP \fB&\fP\fB[\fP\fIoptions\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]]\fP\fB +.br + +\fP\fB[\fP\fI2addr\fP\fB]\fP \fB~\fP\fB[\fP\fIoptions\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]]\fP +.fi +.RE +.sp +.LP +Replace the first instance of the pattern \fIpattern\fP by the string +\fIrepl\fP on each specified line. (See Regular Expressions in ex +and Replacement Strings in ex .) Any +non-alphabetic, non- <blank> delimiter other than \fB'\\'\fP, \fB'|'\fP, +double quote, or <newline> can be used +instead of \fB'/'\fP . Backslash characters can be used to escape +delimiters, backslash characters, and other special +characters. +.LP +The trailing delimiter can be omitted from \fIpattern\fP or from \fIrepl\fP +at the end of the command line. If both +\fIpattern\fP and \fIrepl\fP are not specified or are empty (for example, +\fB"//"\fP ), the last \fBs\fP command shall be +repeated. If only \fIpattern\fP is not specified or is empty, the +last regular expression used in the editor shall be used as the +pattern. If only \fIrepl\fP is not specified or is empty, the pattern +shall be replaced by nothing. If the entire replacement +pattern is \fB'%'\fP, the last replacement pattern to an \fBs\fP +command shall be used. +.LP +Entering a <carriage-return> in \fIrepl\fP (which requires an escaping +backslash in \fIex\fP mode and an escaping +<control>-V in open or \fIvi\fP mode) shall split the line at that +point, creating a new +line in the edit buffer. The <carriage-return> shall be discarded. +.LP +If \fIoptions\fP includes the letter \fB'g'\fP ( \fBglobal\fP), all +non-overlapping instances of the pattern in the line +shall be replaced. +.LP +If \fIoptions\fP includes the letter \fB'c'\fP ( \fBconfirm\fP), then +before each substitution the line shall be written; +the written line shall reflect all previous substitutions. On the +following line, <space>s shall be written beneath the +characters from the line that are before the \fIpattern\fP to be replaced, +and \fB'^'\fP characters written beneath the +characters included in the \fIpattern\fP to be replaced. The \fIex\fP +utility shall then wait for a response from the user. An +affirmative response shall cause the substitution to be done, while +any other input shall not make the substitution. An affirmative +response shall consist of a line with the affirmative response (as +defined by the current locale) at the beginning of the line. +This line shall be subject to editing in the same way as the \fIex\fP +command line. +.LP +If interrupted (see the ASYNCHRONOUS EVENTS section), any modifications +confirmed by the user shall be preserved in the edit +buffer after the interrupt. +.LP +If the remembered search direction is not set, the \fBs\fP command +shall set it to forward. +.LP +In the second Synopsis, the \fB&\fP command shall repeat the previous +substitution, as if the \fB&\fP command were +replaced by: +.sp +.RS +.nf + +\fBs/\fP\fIpattern\fP\fB/\fP\fIrepl\fP\fB/ +\fP +.fi +.RE +.LP +where \fIpattern\fP and \fIrepl\fP are as specified in the previous +\fBs\fP, \fB&\fP, or \fB~\fP command. +.LP +In the third Synopsis, the \fB~\fP command shall repeat the previous +substitution, as if the \fB'~'\fP were +replaced by: +.sp +.RS +.nf + +\fBs/\fP\fIpattern\fP\fB/\fP\fIrepl\fP\fB/ +\fP +.fi +.RE +.LP +where \fIpattern\fP shall be the last regular expression specified +to the editor, and \fIrepl\fP shall be from the previous +substitution (including \fB&\fP and \fB~\fP) command. +.LP +These commands shall be affected by the \fILC_MESSAGES\fP environment +variable. +.LP +\fICurrent line\fP: Set to the last line in which a substitution occurred, +or, unchanged if no substitution occurred. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Suspend +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBsu\fP\fB[\fP\fBspend\fP\fB][\fP\fB!\fP\fB]\fP\fBst\fP\fB[\fP\fBop\fP\fB][\fP\fB!\fP\fB]\fP +.fi +.RE +.sp +.LP +Allow control to return to the invoking process; \fIex\fP shall suspend +itself as if it had received the SIGTSTP signal. The +suspension shall occur only if job control is enabled in the invoking +shell (see the description of \fIset\fP \fB-m\fP). +.LP +These commands shall be affected by the \fBautowrite\fP and \fBwriteany\fP +edit options. +.LP +The current \fBsusp\fP character (see \fIstty\fP ) shall be equivalent +to the \fBsuspend\fP +command. +.SS Tag +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBta\fP\fB[\fP\fBg\fP\fB][\fP\fB!\fP\fB]\fP \fItagstring\fP +.fi +.RE +.sp +.LP +The results are unspecified if the format of a tags file is not as +specified by the \fIctags\fP utility (see \fIctags\fP ) description. +.LP +The \fBtag\fP command shall search for \fItagstring\fP in the tag +files referred to by the \fBtag\fP edit option, in the +order they are specified, until a reference to \fItagstring\fP is +found. Files shall be searched from beginning to end. If no +reference is found, it shall be an error and an error message to this +effect shall be written. If the reference is not found, or if +an error occurs while processing a file referred to in the \fBtag\fP +edit option, it shall be an error, and an error message shall +be written at the first occurrence of such an error. +.LP +Otherwise, if the tags file contained a pattern, the pattern shall +be treated as a regular expression used in the editor; for +example, for the purposes of the \fBs\fP command. +.LP +If the \fItagstring\fP is in a file with a different name than the +current pathname, set the current pathname to the name of +that file, and replace the contents of the edit buffer with the contents +of that file. In this case, if no \fB'!'\fP is appended +to the command name, and the edit buffer has been modified since the +last complete write, it shall be an error, unless the file is +successfully written as specified by the \fBautowrite\fP option. +.LP +This command shall be affected by the \fBautowrite\fP, \fBtag\fP, +\fBtaglength\fP, and \fBwriteany\fP edit options. +.LP +\fICurrent line\fP: If the tags file contained a line number, set +to that line number. If the line number is larger than the +last line in the edit buffer, an error message shall be written and +the current line shall be set as specified for the \fBedit\fP +command. +.LP +If the tags file contained a pattern, set to the first occurrence +of the pattern in the file. If no matching pattern is found, +an error message shall be written and the current line shall be set +as specified for the \fBedit\fP command. +.LP +\fICurrent column\fP: If the tags file contained a line-number reference +and that line-number was not larger than the last line +in the edit buffer, or if the tags file contained a pattern and that +pattern was found, set to non- <blank>. Otherwise, set +as specified for the \fBedit\fP command. +.SS Unabbreviate +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBuna\fP\fB[\fP\fBbbrev\fP\fB]\fP \fIlhs\fP +.fi +.RE +.sp +.LP +If \fIlhs\fP is not an entry in the current list of abbreviations +(see Abbreviate ), it shall be +an error. Otherwise, delete \fIlhs\fP from the list of abbreviations. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Undo +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBu\fP\fB[\fP\fBndo\fP\fB]\fP +.fi +.RE +.sp +.LP +Reverse the changes made by the last command that modified the contents +of the edit buffer, including \fBundo\fP. For this +purpose, the \fBglobal\fP, \fBv\fP, \fBopen\fP, and \fBvisual\fP commands, +and commands resulting from buffer executions and +mapped character expansions, are considered single commands. +.LP +If no action that can be undone preceded the \fBundo\fP command, it +shall be an error. +.LP +If the \fBundo\fP command restores lines that were marked, the mark +shall also be restored unless it was reset subsequent to +the deletion of the lines. +.LP +\fICurrent line\fP: +.IP " 1." 4 +If lines are added or changed in the file, set to the first line added +or changed. +.LP +.IP " 2." 4 +Set to the line before the first line deleted, if it exists. +.LP +.IP " 3." 4 +Set to 1 if the edit buffer is not empty. +.LP +.IP " 4." 4 +Set to zero. +.LP +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Unmap +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBunm\fP\fB[\fP\fBap\fP\fB][\fP\fB!\fP\fB]\fP \fIlhs\fP +.fi +.RE +.sp +.LP +If \fB'!'\fP is appended to the command name, and if \fIlhs\fP is +not an entry in the list of text input mode map +definitions, it shall be an error. Otherwise, delete \fIlhs\fP from +the list of text input mode map definitions. +.LP +If no \fB'!'\fP is appended to the command name, and if \fIlhs\fP +is not an entry in the list of command mode map +definitions, it shall be an error. Otherwise, delete \fIlhs\fP from +the list of command mode map definitions. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Version +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fBve\fP\fB[\fP\fBrsion\fP\fB]\fP +.fi +.RE +.sp +.LP +Write a message containing version information for the editor. The +format of the message is unspecified. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Visual +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBvi\fP\fB[\fP\fBsual\fP\fB][\fP\fItype\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +If \fIex\fP is currently in open or visual mode, the Synopsis and +behavior of the visual command shall be the same as the +\fBedit\fP command, as specified by Edit . +.LP +Otherwise, this command need not be supported on block-mode terminals +or terminals with insufficient capabilities. If standard +input, standard output, or standard error are not terminal devices, +the results are unspecified. +.LP +If \fIcount\fP is specified, the value of the \fBwindow\fP edit option +shall be set to \fIcount\fP (as described in window ). If the \fB'^'\fP +type character was also specified, the \fBwindow\fP edit option shall +be set +before being used by the type character. +.LP +Enter visual mode. If \fItype\fP is not specified, it shall be as +if a \fItype\fP of \fB'+'\fP was specified. The +\fItype\fP shall cause the following effects: +.TP 7 +\fB+\fP +Place the beginning of the specified line at the top of the display. +.TP 7 +\fB-\fP +Place the end of the specified line at the bottom of the display. +.TP 7 +\fB\&.\fP +Place the beginning of the specified line in the middle of the display. +.TP 7 +\fB^\fP +If the specified line is less than or equal to the value of the \fBwindow\fP +edit option, set the line to 1; otherwise, +decrement the line by the value of the \fBwindow\fP edit option minus +1. Place the beginning of this line as close to the bottom +of the displayed lines as possible, while still displaying the value +of the \fBwindow\fP edit option number of lines. +.sp +.LP +\fICurrent line\fP: Set to the specified line. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Write +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBw\fP\fB[\fP\fBrite\fP\fB][\fP\fB!\fP\fB][\fP\fB>>\fP\fB][\fP\fIfile\fP\fB] +[\fP\fI2addr\fP\fB]\fP \fBw\fP\fB[\fP\fBrite\fP\fB][\fP\fB!\fP\fB][\fP\fIfile\fP\fB] +[\fP\fI2addr\fP\fB]\fP \fBwq\fP\fB[\fP\fB!\fP\fB][\fP\fB>>\fP\fB][\fP\fIfile\fP\fB]\fP +.fi +.RE +.sp +.LP +If no lines are specified, the lines shall default to the entire file. +.LP +The command \fBwq\fP shall be equivalent to a \fBwrite\fP command +followed by a \fBquit\fP command; \fBwq!\fP shall be +equivalent to \fBwrite!\fP followed by \fBquit\fP. In both cases, +if the \fBwrite\fP command fails, the \fBquit\fP shall not be +attempted. +.LP +If the command name is not followed by one or more <blank>s, or \fIfile\fP +is not preceded by a \fB'!'\fP character, +the \fBwrite\fP shall be to a file. +.IP " 1." 4 +If the \fB>>\fP argument is specified, and the file already exists, +the lines shall be appended to the file instead of +replacing its contents. If the \fB>>\fP argument is specified, and +the file does not already exist, it is unspecified +whether the write shall proceed as if the \fB>>\fP argument had not +been specified or if the write shall fail. +.LP +.IP " 2." 4 +If the \fBreadonly\fP edit option is set (see readonly ), the \fBwrite\fP +shall fail. +.LP +.IP " 3." 4 +If \fIfile\fP is specified, and is not the current pathname, and the +file exists, the \fBwrite\fP shall fail. +.LP +.IP " 4." 4 +If \fIfile\fP is not specified, the current pathname shall be used. +If there is no current pathname, the \fBwrite\fP command +shall fail. +.LP +.IP " 5." 4 +If the current pathname is used, and the current pathname has been +changed by the \fBfile\fP or \fBread\fP commands, and the +file exists, the \fBwrite\fP shall fail. If the \fBwrite\fP is successful, +subsequent \fBwrite\fPs shall not fail for this +reason (unless the current pathname is changed again). +.LP +.IP " 6." 4 +If the whole edit buffer is not being written, and the file to be +written exists, the \fBwrite\fP shall fail. +.LP +.LP +For rules 1., 2., 4., and 5., the \fBwrite\fP can be forced by appending +the character \fB'!'\fP to the command name. +.LP +For rules 2., 4., and 5., the \fBwrite\fP can be forced by setting +the \fBwriteany\fP edit option. +.LP +Additional, implementation-defined tests may cause the \fBwrite\fP +to fail. +.LP +If the edit buffer is empty, a file without any contents shall be +written. +.LP +An informational message shall be written noting the number of lines +and bytes written. +.LP +Otherwise, if the command is followed by one or more <blank>s, and +the file is preceded by \fB'!'\fP, the rest of the +line after the \fB'!'\fP shall have \fB'%'\fP, \fB'#'\fP, and \fB'!'\fP +characters expanded as described in Command Line Parsing in ex . +.LP +The \fIex\fP utility shall then pass two arguments to the program +named by the \fBshell\fP edit option; the first shall be +\fB-c\fP and the second shall be the expanded arguments to the \fBwrite\fP +command as a single argument. The specified lines +shall be written to the standard input of the command. The standard +error and standard output of the program, if any, shall be +written as described for the \fBprint\fP command. If the last character +in that output is not a <newline>, a <newline> +shall be written at the end of the output. +.LP +The special meaning of the \fB'!'\fP following the \fBwrite\fP command +can be overridden by escaping it with a backslash +character. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Write and Exit +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBx\fP\fB[\fP\fBit\fP\fB][\fP\fB!\fP\fB][\fP\fIfile\fP\fB]\fP +.fi +.RE +.sp +.LP +If the edit buffer has not been modified since the last complete \fBwrite\fP, +\fBxit\fP shall be equivalent to the \fBquit\fP +command, or if a \fB'!'\fP is appended to the command name, to \fBquit!\fP. +.LP +Otherwise, \fBxit\fP shall be equivalent to the \fBwq\fP command, +or if a \fB'!'\fP is appended to the command name, to +\fBwq!\fP. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Yank +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fBya\fP\fB[\fP\fBnk\fP\fB][\fP\fIbuffer\fP\fB][\fP\fIcount\fP\fB]\fP +.fi +.RE +.sp +.LP +Copy the specified lines to the specified buffer (by default, the +unnamed buffer), which shall become a line-mode buffer. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Adjust Window +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fBz\fP\fB[\fP\fB!\fP\fB][\fP\fItype\fP \fB...\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +If no line is specified, the current line shall be the default; if +\fItype\fP is omitted as well, the current line value shall +first be incremented by 1. If incrementing the current line would +cause it to be greater than the last line in the edit buffer, it +shall be an error. +.LP +If there are <blank>s between the \fItype\fP argument and the preceding +\fBz\fP command name or optional \fB'!'\fP +character, it shall be an error. +.LP +If \fIcount\fP is specified, the value of the \fBwindow\fP edit option +shall be set to \fIcount\fP (as described in window ). If \fIcount\fP +is omitted, it shall default to 2 times the value of the \fBscroll\fP +edit +option, or if \fB!\fP was specified, the number of lines in the display +minus 1. +.LP +If \fItype\fP is omitted, then \fIcount\fP lines starting with the +specified line shall be written. Otherwise, \fIcount\fP +lines starting with the line specified by the \fItype\fP argument +shall be written. +.LP +The \fItype\fP argument shall change the lines to be written. The +possible values of \fItype\fP are as follows: +.TP 7 +\fB-\fP +The specified line shall be decremented by the following value: +.sp +.RS +.nf + +\fB(((number of "-" characters) x\fP \fIcount\fP\fB) -1) +\fP +.fi +.RE +.LP +If the calculation would result in a number less than 1, it shall +be an error. Write lines from the edit buffer, starting at the +new value of line, until \fIcount\fP lines or the last line in the +edit buffer has been written. +.TP 7 +\fB+\fP +The specified line shall be incremented by the following value: +.sp +.RS +.nf + +\fB(((number of "+" characters) -1) x\fP \fIcount\fP\fB) +1 +\fP +.fi +.RE +.LP +If the calculation would result in a number greater than the last +line in the edit buffer, it shall be an error. Write lines +from the edit buffer, starting at the new value of line, until \fIcount\fP +lines or the last line in the edit buffer has been +written. +.TP 7 +\fB=\fP,\fB.\fP +If more than a single \fB'.'\fP or \fB'='\fP is specified, it shall +be an error. The following steps shall be taken: +.RS +.IP " 1." 4 +If \fIcount\fP is zero, nothing shall be written. +.LP +.IP " 2." 4 +Write as many of the \fIN\fP lines before the current line in the +edit buffer as exist. If \fIcount\fP or \fB'!'\fP was +specified, \fIN\fP shall be: +.sp +.RS +.nf + +\fB(\fP\fIcount\fP \fB-1) /2 +\fP +.fi +.RE +.LP +Otherwise, \fIN\fP shall be: +.sp +.RS +.nf + +\fB(\fP\fIcount\fP \fB-3) /2 +\fP +.fi +.RE +.LP +If \fIN\fP is a number less than 3, no lines shall be written. +.LP +.IP " 3." 4 +If \fB'='\fP was specified as the type character, write a line consisting +of the smaller of the number of columns in the +display divided by two, or 40 \fB'-'\fP characters. +.LP +.IP " 4." 4 +Write the current line. +.LP +.IP " 5." 4 +Repeat step 3. +.LP +.IP " 6." 4 +Write as many of the \fIN\fP lines after the current line in the edit +buffer as exist. \fIN\fP shall be defined as in step 2. +If \fIN\fP is a number less than 3, no lines shall be written. If +\fIcount\fP is less than 3, no lines shall be written. +.LP +.RE +.TP 7 +\fB^\fP +The specified line shall be decremented by the following value: +.sp +.RS +.nf + +\fB(((number of "^" characters) +1) x\fP \fIcount\fP\fB) -1 +\fP +.fi +.RE +.LP +If the calculation would result in a number less than 1, it shall +be an error. Write lines from the edit buffer, starting at the +new value of line, until \fIcount\fP lines or the last line in the +edit buffer has been written. +.sp +.LP +\fICurrent line\fP: Set to the last line written, unless the type +is \fB=\fP, in which case, set to the specified line. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Escape +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB!\fP \fIcommand +\fP\fB[\fP\fIaddr\fP\fB]\fP\fB!\fP \fIcommand\fP +.fi +.RE +.sp +.LP +The contents of the line after the \fB'!'\fP shall have \fB'%'\fP, +\fB'#'\fP, and \fB'!'\fP characters expanded as +described in Command Line Parsing in ex . If the expansion causes +the text of the line to change, it +shall be redisplayed, preceded by a single \fB'!'\fP character. +.LP +The \fIex\fP utility shall execute the program named by the \fBshell\fP +edit option. It shall pass two arguments to the +program; the first shall be \fB-c\fP, and the second shall be the +expanded arguments to the \fB!\fP command as a single +argument. +.LP +If no lines are specified, the standard input, standard output, and +standard error of the program shall be set to the standard +input, standard output, and standard error of the \fIex\fP program +when it was invoked. In addition, a warning message shall be +written if the edit buffer has been modified since the last complete +write, and the \fBwarn\fP edit option is set. +.LP +If lines are specified, they shall be passed to the program as standard +input, and the standard output and standard error of the +program shall replace those lines in the edit buffer. Each line in +the program output (as delimited by <newline>s or the end +of the output if it is not immediately preceded by a <newline>), shall +be a separate line in the edit buffer. Any occurrences +of <carriage-return> and <newline> pairs in the output shall be treated +as single <newline>s. The specified lines +shall be copied into the unnamed buffer before they are replaced, +and the unnamed buffer shall become a line-mode buffer. +.LP +If in \fIex\fP mode, a single \fB'!'\fP character shall be written +when the program completes. +.LP +This command shall be affected by the \fBshell\fP and \fBwarn\fP edit +options. If no lines are specified, this command shall +be affected by the \fBautowrite\fP and \fBwriteany\fP edit options. +If lines are specified, this command shall be affected by the +\fBautoprint\fP edit option. +.LP +\fICurrent line\fP: +.IP " 1." 4 +If no lines are specified, unchanged. +.LP +.IP " 2." 4 +Otherwise, set to the last line read in, if any lines are read in. +.LP +.IP " 3." 4 +Otherwise, set to the line before the first line of the lines specified, +if that line exists. +.LP +.IP " 4." 4 +Otherwise, set to the first line of the edit buffer if the edit buffer +is not empty. +.LP +.IP " 5." 4 +Otherwise, set to zero. +.LP +.LP +\fICurrent column\fP: If no lines are specified, unchanged. Otherwise, +set to non- <blank>. +.SS Shift Left +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fB<\fP\fB[\fP\fB< ...\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +Shift the specified lines to the start of the line; the number of +column positions to be shifted shall be the number of command +characters times the value of the \fBshiftwidth\fP edit option. Only +leading <blank>s shall be deleted or changed into other +<blank>s in shifting; other characters shall not be affected. +.LP +Lines to be shifted shall be copied into the unnamed buffer, which +shall become a line-mode buffer. +.LP +This command shall be affected by the \fBautoprint\fP edit option. +.LP +\fICurrent line\fP: Set to the last line in the lines specified. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Shift Right +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fB>\fP\fB[\fP\fB> ...\fP\fB][\fP\fIcount\fP\fB][\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +Shift the specified lines away from the start of the line; the number +of column positions to be shifted shall be the number of +command characters times the value of the \fBshiftwidth\fP edit option. +The shift shall be accomplished by adding <blank>s +as a prefix to the line or changing leading <blank>s into other <blank>s. +Empty lines shall not be changed. +.LP +Lines to be shifted shall be copied into the unnamed buffer, which +shall become a line-mode buffer. +.LP +This command shall be affected by the \fBautoprint\fP edit option. +.LP +\fICurrent line\fP: Set to the last line in the lines specified. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS <control>-D +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB<control>-D +\fP +.fi +.RE +.sp +.LP +Write the next \fIn\fP lines, where \fIn\fP is the minimum of the +values of the \fBscroll\fP edit option and the number of +lines after the current line in the edit buffer. If the current line +is the last line of the edit buffer it shall be an error. +.LP +\fICurrent line\fP: Set to the last line written. +.LP +\fICurrent column\fP: Set to non- <blank>. +.SS Write Line Number +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI1addr\fP\fB]\fP \fB=\fP \fB[\fP\fIflags\fP\fB]\fP +.fi +.RE +.sp +.LP +If \fIline\fP is not specified, it shall default to the last line +in the edit buffer. Write the line number of the specified +line. +.LP +\fICurrent line\fP: Unchanged. +.LP +\fICurrent column\fP: Unchanged. +.SS Execute +.TP 7 +\fISynopsis\fP: +.sp +.RS +.nf + +\fB[\fP\fI2addr\fP\fB]\fP \fB@\fP \fIbuffer\fP\fB[\fP\fI2addr\fP\fB]\fP \fB*\fP \fIbuffer\fP +.fi +.RE +.sp +.LP +If no buffer is specified or is specified as \fB'@'\fP or \fB'*'\fP, +the last buffer executed shall be used. If no +previous buffer has been executed, it shall be an error. +.LP +For each line specified by the addresses, set the current line ( \fB'.'\fP +) to the specified line, and execute the contents +of the named \fIbuffer\fP (as they were at the time the \fB@\fP command +was executed) as \fIex\fP commands. For each line of a +line-mode buffer, and all but the last line of a character-mode buffer, +the \fIex\fP command parser shall behave as if the line +was terminated by a <newline>. +.LP +If an error occurs during this process, or a line specified by the +addresses does not exist when the current line would be set +to it, or more than a single line was specified by the addresses, +and the contents of the edit buffer are replaced (for example, by +the \fIex\fP \fB:edit\fP command) an error message shall be written, +and no more commands resulting from the execution of this +command shall be processed. +.LP +\fICurrent line\fP: As specified for the individual \fIex\fP commands. +.LP +\fICurrent column\fP: As specified for the individual \fIex\fP commands. +.SS Regular Expressions in ex +.LP +The \fIex\fP utility shall support regular expressions that are a +superset of the basic regular expressions described in the +Base Definitions volume of IEEE\ Std\ 1003.1-2001, Section 9.3, Basic +Regular Expressions. A null regular expression ( \fB"//"\fP ) shall +be equivalent to the last regular expression +encountered. +.LP +Regular expressions can be used in addresses to specify lines and, +in some commands (for example, the \fBsubstitute\fP +command), to specify portions of a line to be substituted. +.LP +The following constructs can be used to enhance the basic regular +expressions: +.TP 7 +\fB\\<\fP +Match the beginning of a \fIword\fP. (See the definition of \fIword\fP +at the beginning of Command +Descriptions in ex .) +.TP 7 +\fB\\>\fP +Match the end of a \fIword\fP. +.TP 7 +\fB~\fP +Match the replacement part of the last \fBsubstitute\fP command. The +tilde ( \fB'~'\fP ) character can be escaped in a +regular expression to become a normal character with no special meaning. +The backslash shall be discarded. +.sp +.LP +When the editor option \fBmagic\fP is not set, the only characters +with special meanings shall be \fB'^'\fP at the beginning +of a pattern, \fB'$'\fP at the end of a pattern, and \fB'\\'\fP . +The characters \fB'.'\fP, \fB'*'\fP, \fB'['\fP, +and \fB'~'\fP shall be treated as ordinary characters unless preceded +by a \fB'\\'\fP ; when preceded by a \fB'\\'\fP +they shall regain their special meaning, or in the case of backslash, +be handled as a single backslash. Backslashes used to escape +other characters shall be discarded. +.SS Replacement Strings in ex +.LP +The character \fB'&'\fP ( \fB'\\&'\fP if the editor option \fBmagic\fP +is not set) in the replacement string shall +stand for the text matched by the pattern to be replaced. The character +\fB'~'\fP ( \fB'\\~'\fP if \fBmagic\fP is +not set) shall be replaced by the replacement part of the previous +\fBsubstitute\fP command. The sequence \fB'\\n'\fP, where +\fIn\fP is an integer, shall be replaced by the text matched by the +pattern enclosed in the \fIn\fPth set of parentheses +\fB'\\('\fP and \fB'\\)'\fP . +.LP +The strings \fB'\\l'\fP, \fB'\\u'\fP, \fB'\\L'\fP, and \fB'\\U'\fP +can be used to modify the case of elements in the +replacement string (using the \fB'\\&'\fP or \fB"\\"\fP digit) notation. +The string \fB'\\l'\fP ( \fB'\\u'\fP ) shall +cause the character that follows to be converted to lowercase (uppercase). +The string \fB'\\L'\fP ( \fB'\\U'\fP ) shall cause +all characters subsequent to it to be converted to lowercase (uppercase) +as they are inserted by the substitution until the string +\fB'\\e'\fP or \fB'\\E'\fP, or the end of the replacement string, +is encountered. +.LP +Otherwise, any character following a backslash shall be treated as +that literal character, and the escaping backslash shall be +discarded. +.LP +An example of case conversion with the \fBs\fP command is as follows: +.sp +.RS +.nf + +\fB:\fP\fBp +\fP\fBThe cat sat on the mat. +:\fP\fBs/\\<.at\\>/\\u&/gp +\fP\fBThe Cat Sat on the Mat. +:\fP\fBs/S\\(.*\\)M/S\\U\\1\\eM/p +\fP\fBThe Cat SAT ON THE Mat.\fP +.fi +.RE +.SS Edit Options in ex +.LP +The \fIex\fP utility has a number of options that modify its behavior. +These options have default settings, which can be +changed using the \fBset\fP command. +.LP +Options are Boolean unless otherwise specified. +.SS autoindent, ai +.LP +[Default \fIunset\fP] +.LP +If \fBautoindent\fP is set, each line in input mode shall be indented +(using first as many <tab>s as possible, as +determined by the editor option \fBtabstop\fP, and then using <space>s) +to align with another line, as follows: +.IP " 1." 4 +If in open or visual mode and the text input is part of a line-oriented +command (see the EXTENDED DESCRIPTION in \fIvi\fP ), align to the +first column. +.LP +.IP " 2." 4 +Otherwise, if in open or visual mode, indentation for each line shall +be set as follows: +.RS +.IP " a." 4 +If a line was previously inserted as part of this command, it shall +be set to the indentation of the last inserted line by +default, or as otherwise specified for the <control>-D character in +\fIInput Mode Commands +in vi\fP . +.LP +.IP " b." 4 +Otherwise, it shall be set to the indentation of the previous current +line, if any; otherwise, to the first column. +.LP +.RE +.LP +.IP " 3." 4 +For the \fIex\fP \fBa\fP, \fBi\fP, and \fBc\fP commands, indentation +for each line shall be set as follows: +.RS +.IP " a." 4 +If a line was previously inserted as part of this command, it shall +be set to the indentation of the last inserted line by +default, or as otherwise specified for the \fIeof\fP character in +Scroll . +.LP +.IP " b." 4 +Otherwise, if the command is the \fIex\fP \fBa\fP command, it shall +be set to the line appended after, if any; otherwise to +the first column. +.LP +.IP " c." 4 +Otherwise, if the command is the \fIex\fP \fBi\fP command, it shall +be set to the line inserted before, if any; otherwise to +the first column. +.LP +.IP " d." 4 +Otherwise, if the command is the \fIex\fP \fBc\fP command, it shall +be set to the indentation of the line replaced. +.LP +.RE +.LP +.SS autoprint, ap +.LP +[Default \fIset\fP] +.LP +If \fBautoprint\fP is set, the current line shall be written after +each \fIex\fP command that modifies the contents of the +current edit buffer, and after each \fBtag\fP command for which the +tag search pattern was found or tag line number was valid, +unless: +.IP " 1." 4 +The command was executed while in open or visual mode. +.LP +.IP " 2." 4 +The command was executed as part of a \fBglobal\fP or \fBv\fP command +or \fB@\fP buffer execution. +.LP +.IP " 3." 4 +The command was the form of the \fBread\fP command that reads a file +into the edit buffer. +.LP +.IP " 4." 4 +The command was the \fBappend\fP, \fBchange\fP, or \fBinsert\fP command. +.LP +.IP " 5." 4 +The command was not terminated by a <newline>. +.LP +.IP " 6." 4 +The current line shall be written by a flag specified to the command; +for example, \fBdelete #\fP shall write the current line +as specified for the flag modifier to the \fBdelete\fP command, and +not as specified by the \fBautoprint\fP edit option. +.LP +.SS autowrite, aw +.LP +[Default \fIunset\fP] +.LP +If \fBautowrite\fP is set, and the edit buffer has been modified since +it was last completely written to any file, the contents +of the edit buffer shall be written as if the \fIex\fP \fBwrite\fP +command had been specified without arguments, before each +command affected by the \fBautowrite\fP edit option is executed. Appending +the character \fB'!'\fP to the command name of any +of the \fIex\fP commands except \fB'!'\fP shall prevent the write. +If the write fails, it shall be an error and the command +shall not be executed. +.SS beautify, bf +.LP +[Default \fIunset\fP] +.LP +If \fBbeautify\fP is set, all non-printable characters, other than +<tab>s, <newline>s, and <form-feed>s, +shall be discarded from text read in from files. +.SS directory, dir +.LP +[Default \fIimplementation-defined\fP] +.LP +The value of this option specifies the directory in which the editor +buffer is to be placed. If this directory is not writable +by the user, the editor shall quit. +.SS edcompatible, ed +.LP +[Default \fIunset\fP] +.LP +Causes the presence of \fBg\fP and \fBc\fP suffixes on substitute +commands to be remembered, and toggled by repeating the +suffixes. +.SS errorbells, eb +.LP +[Default \fIunset\fP] +.LP +If the editor is in \fIex\fP mode, and the terminal does not support +a standout mode (such as inverse video), and +\fBerrorbells\fP is set, error messages shall be preceded by alerting +the terminal. +.SS exrc +.LP +[Default \fIunset\fP] +.LP +If \fBexrc\fP is set, \fIex\fP shall access any \fB.exrc\fP file in +the current directory, as described in Initialization in ex and vi +\&. If \fBexrc\fP is not set, \fIex\fP shall ignore any \fB.exrc\fP +file in the +current directory during initialization, unless the current directory +is that named by the \fIHOME\fP environment variable. +.SS ignorecase, ic +.LP +[Default \fIunset\fP] +.LP +If \fBignorecase\fP is set, characters that have uppercase and lowercase +representations shall have those representations +considered as equivalent for purposes of regular expression comparison. +.LP +The \fBignorecase\fP edit option shall affect all remembered regular +expressions; for example, unsetting the \fBignorecase\fP +edit option shall cause a subsequent \fIvi\fP \fBn\fP command to search +for the last basic +regular expression in a case-sensitive fashion. +.SS list +.LP +[Default \fIunset\fP] +.LP +If \fBlist\fP is set, edit buffer lines written while in \fIex\fP +command mode shall be written as specified for the +\fBprint\fP command with the \fBl\fP flag specified. In open or visual +mode, each edit buffer line shall be displayed as +specified for the \fIex\fP \fBprint\fP command with the \fBl\fP flag +specified. In open or visual text input mode, when the +cursor does not rest on any character in the line, it shall rest on +the \fB'$'\fP marking the end of the line. +.SS magic +.LP +[Default \fIset\fP] +.LP +If \fBmagic\fP is set, modify the interpretation of characters in +regular expressions and substitution replacement strings (see +Regular Expressions in ex and Replacement Strings in ex ). +.SS mesg +.LP +[Default \fIset\fP] +.LP +If \fBmesg\fP is set, the permission for others to use the \fBwrite\fP +or \fBtalk\fP commands to write to the terminal shall +be turned on while in open or visual mode. The shell-level command +\fImesg\fP \fBn\fP shall +take precedence over any setting of the \fIex\fP \fBmesg\fP option; +that is, if \fBmesg y\fP was issued before the editor +started (or in a shell escape), such as: +.sp +.RS +.nf + +\fB:!mesg y +\fP +.fi +.RE +.LP +the \fBmesg\fP option in \fIex\fP shall suppress incoming messages, +but the \fBmesg\fP option shall not enable incoming +messages if \fBmesg n\fP was issued. +.SS number, nu +.LP +[Default \fIunset\fP] +.LP +If \fBnumber\fP is set, edit buffer lines written while in \fIex\fP +command mode shall be written with line numbers, in the +format specified by the \fBprint\fP command with the \fB#\fP flag +specified. In \fIex\fP text input mode, each line shall be +preceded by the line number it will have in the file. +.LP +In open or visual mode, each edit buffer line shall be displayed with +a preceding line number, in the format specified by the +\fIex\fP \fBprint\fP command with the \fB#\fP flag specified. This +line number shall not be considered part of the line for the +purposes of evaluating the current column; that is, column position +1 shall be the first column position after the format specified +by the \fBprint\fP command. +.SS paragraphs, para +.LP +[Default in the POSIX locale \fBIPLPPPQPP LIpplpipbp\fP] +.LP +The \fBparagraphs\fP edit option shall define additional paragraph +boundaries for the open and visual mode commands. The +\fBparagraphs\fP edit option can be set to a character string consisting +of zero or more character pairs. It shall be an error to +set it to an odd number of characters. +.SS prompt +.LP +[Default \fIset\fP] +.LP +If \fBprompt\fP is set, \fIex\fP command mode input shall be prompted +for with a colon ( \fB':'\fP ); when unset, no prompt +shall be written. +.SS readonly +.LP +[Default \fIsee text\fP] +.LP +If the \fBreadonly\fP edit option is set, read-only mode shall be +enabled (see Write ). The +\fBreadonly\fP edit option shall be initialized to set if either of +the following conditions are true: +.IP " *" 3 +The command-line option -R was specified. +.LP +.IP " *" 3 +Performing actions equivalent to the \fIaccess\fP() function called +with the following +arguments indicates that the file lacks write permission: +.RS +.IP " 1." 4 +The current pathname is used as the \fIpath\fP argument. +.LP +.IP " 2." 4 +The constant \fBW_OK\fP is used as the \fIamode\fP argument. +.LP +.RE +.LP +.LP +The \fBreadonly\fP edit option may be initialized to set for other, +implementation-defined reasons. The \fBreadonly\fP edit +option shall not be initialized to unset based on any special privileges +of the user or process. The \fBreadonly\fP edit option +shall be reinitialized each time that the contents of the edit buffer +are replaced (for example, by an \fBedit\fP or \fBnext\fP +command) unless the user has explicitly set it, in which case it shall +remain set until the user explicitly unsets it. Once unset, +it shall again be reinitialized each time that the contents of the +edit buffer are replaced. +.SS redraw +.LP +[Default \fIunset\fP] +.LP +The editor simulates an intelligent terminal on a dumb terminal. (Since +this is likely to require a large amount of output to +the terminal, it is useful only at high transmission speeds.) +.SS remap +.LP +[Default \fIset\fP] +.LP +If \fBremap\fP is set, map translation shall allow for maps defined +in terms of other maps; translation shall continue until a +final product is obtained. If unset, only a one-step translation shall +be done. +.SS report +.LP +[Default 5] +.LP +The value of this \fBreport\fP edit option specifies what number of +lines being added, copied, deleted, or modified in the edit +buffer will cause an informational message to be written to the user. +The following conditions shall cause an informational +message. The message shall contain the number of lines added, copied, +deleted, or modified, but is otherwise unspecified. +.IP " *" 3 +An \fIex\fP or \fIvi\fP editor command, other than \fBopen\fP, \fBundo\fP, +or +\fBvisual\fP, that modifies at least the value of the \fBreport\fP +edit option number of lines, and which is not part of an +\fIex\fP \fBglobal\fP or \fBv\fP command, or \fIex\fP or \fIvi\fP +buffer execution, shall +cause an informational message to be written. +.LP +.IP " *" 3 +An \fIex\fP \fByank\fP or \fIvi\fP \fBy\fP or \fBY\fP command, that +copies at least the +value of the \fBreport\fP edit option plus 1 number of lines, and +which is not part of an \fIex\fP \fBglobal\fP or \fBv\fP +command, or \fIex\fP or \fIvi\fP buffer execution, shall cause an +informational message to be +written. +.LP +.IP " *" 3 +An \fIex\fP \fBglobal\fP, \fBv\fP, \fBopen\fP, \fBundo\fP, or \fBvisual\fP +command or \fIex\fP or \fIvi\fP buffer execution, that adds or deletes +a total of at least the value of the \fBreport\fP edit +option number of lines, and which is not part of an \fIex\fP \fBglobal\fP +or \fBv\fP command, or \fIex\fP or \fIvi\fP buffer execution, shall +cause an informational message to be written. (For example, if 3 lines +were added and 8 lines deleted during an \fIex\fP \fBvisual\fP command, +5 would be the number compared against the \fBreport\fP +edit option after the command completed.) +.LP +.SS scroll, scr +.LP +[Default (number of lines in the display -1)/2] +.LP +The value of the \fBscroll\fP edit option shall determine the number +of lines scrolled by the \fIex\fP <control>-D and +\fBz\fP commands. For the \fIvi\fP <control>-D and <control>-U commands, +it shall +be the initial number of lines to scroll when no previous <control>-D +or <control>-U command has been executed. +.SS sections +.LP +[Default in the POSIX locale \fBNHSHH HUnhsh\fP] +.LP +The \fBsections\fP edit option shall define additional section boundaries +for the open and visual mode commands. The +\fBsections\fP edit option can be set to a character string consisting +of zero or more character pairs; it shall be an error to +set it to an odd number of characters. +.SS shell, sh +.LP +[Default from the environment variable \fISHELL ]\fP +.LP +The value of this option shall be a string. The default shall be taken +from the \fISHELL\fP environment variable. If the +\fISHELL\fP environment variable is null or empty, the \fIsh\fP (see +\fIsh\fP ) utility shall be the default. +.SS shiftwidth, sw +.LP +[Default 8] +.LP +The value of this option shall give the width in columns of an indentation +level used during autoindentation and by the shift +commands ( \fB<\fP and \fB>\fP). +.SS showmatch, sm +.LP +[Default \fIunset\fP] +.LP +The functionality described for the \fBshowmatch\fP edit option need +not be supported on block-mode terminals or terminals with +insufficient capabilities. +.LP +If \fBshowmatch\fP is set, in open or visual mode, when a \fB')'\fP +or \fB'}'\fP is typed, if the matching \fB'('\fP +or \fB'{'\fP is currently visible on the display, the matching \fB'('\fP +or \fB'{'\fP shall be flagged moving the cursor +to its location for an unspecified amount of time. +.SS showmode +.LP +[Default \fIunset\fP] +.LP +If \fBshowmode\fP is set, in open or visual mode, the current mode +that the editor is in shall be displayed on the last line of +the display. Command mode and text input mode shall be differentiated; +other unspecified modes and implementation-defined +information may be displayed. +.SS slowopen +.LP +[Default \fIunset\fP] +.LP +If \fBslowopen\fP is set during open and visual text input modes, +the editor shall not update portions of the display other +than those display line columns that display the characters entered +by the user (see \fIInput +Mode Commands in vi\fP ). +.SS tabstop, ts +.LP +[Default 8] +.LP +The value of this edit option shall specify the column boundary used +by a <tab> in the display (see autoprint, ap and \fIInput Mode Commands +in vi\fP ). +.SS taglength, tl +.LP +[Default zero] +.LP +The value of this edit option shall specify the maximum number of +characters that are considered significant in the +user-specified tag name and in the tag name from the tags file. If +the value is zero, all characters in both tag names shall be +significant. +.SS tags +.LP +[Default \fIsee text\fP] +.LP +The value of this edit option shall be a string of <blank>-delimited +pathnames of files used by the \fBtag\fP command. +The default value is unspecified. +.SS term +.LP +[Default from the environment variable \fITERM ]\fP +.LP +The value of this edit option shall be a string. The default shall +be taken from the \fITERM\fP variable in the environment. If +the \fITERM\fP environment variable is empty or null, the default +is unspecified. The editor shall use the value of this edit +option to determine the type of the display device. +.LP +The results are unspecified if the user changes the value of the term +edit option after editor initialization. +.SS terse +.LP +[Default \fIunset\fP] +.LP +If \fBterse\fP is set, error messages may be less verbose. However, +except for this caveat, error messages are unspecified. +Furthermore, not all error messages need change for different settings +of this option. +.SS warn +.LP +[Default \fIset\fP] +.LP +If \fBwarn\fP is set, and the contents of the edit buffer have been +modified since they were last completely written, the +editor shall write a warning message before certain \fB!\fP commands +(see Escape ). +.SS window +.LP +[Default \fIsee text\fP] +.LP +A value used in open and visual mode, by the <control>-B and <control>-F +commands, and, in visual mode, to specify +the number of lines displayed when the screen is repainted. +.LP +If the \fB-w\fP command-line option is not specified, the default +value shall be set to the value of the \fILINES\fP +environment variable. If the \fILINES\fP environment variable is empty +or null, the default shall be the number of lines in the +display minus 1. +.LP +Setting the \fBwindow\fP edit option to zero or to a value greater +than the number of lines in the display minus 1 (either +explicitly or based on the \fB-w\fP option or the \fILINES\fP environment +variable) shall cause the \fBwindow\fP edit option to +be set to the number of lines in the display minus 1. +.LP +The baud rate of the terminal line may change the default in an implementation-defined +manner. +.SS wrapmargin, wm +.LP +[Default 0] +.LP +If the value of this edit option is zero, it shall have no effect. +.LP +If not in the POSIX locale, the effect of this edit option is implementation-defined. +.LP +Otherwise, it shall specify a number of columns from the ending margin +of the terminal. +.LP +During open and visual text input modes, for each character for which +any part of the character is displayed in a column that is +less than \fBwrapmargin\fP columns from the ending margin of the display +line, the editor shall behave as follows: +.IP " 1." 4 +If the character triggering this event is a <blank>, it, and all immediately +preceding <blank>s on the current line +entered during the execution of the current text input command, shall +be discarded, and the editor shall behave as if the user had +entered a single <newline> instead. In addition, if the next user-entered +character is a <space>, it shall be discarded +as well. +.LP +.IP " 2." 4 +Otherwise, if there are one or more <blank>s on the current line immediately +preceding the last group of inserted non- +<blank>s which was entered during the execution of the current text +input command, the <blank>s shall be replaced as if +the user had entered a single <newline> instead. +.LP +.LP +If the \fBautoindent\fP edit option is set, and the events described +in 1. or 2. are performed, any <blank>s at or after +the cursor in the current line shall be discarded. +.LP +The ending margin shall be determined by the system or overridden +by the user, as described for \fICOLUMNS\fP in the +ENVIRONMENT VARIABLES section and the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +Chapter 8, Environment Variables. +.SS wrapscan, ws +.LP +[Default \fIset\fP] +.LP +If \fBwrapscan\fP is set, searches (the \fIex\fP \fB/\fP or \fB?\fP +addresses, or open and visual mode \fB/\fP, \fB?\fP, +\fBN\fP, and \fBn\fP commands) shall wrap around the beginning or +end of the edit buffer; when unset, searches shall stop at the +beginning or end of the edit buffer. +.SS writeany, wa +.LP +[Default \fIunset\fP] +.LP +If \fBwriteany\fP is set, some of the checks performed when executing +the \fIex\fP \fBwrite\fP commands shall be inhibited, +as described in editor option \fBautowrite\fP. +.SH EXIT STATUS +.LP +The following exit values shall be returned: +.TP 7 +\ 0 +Successful completion. +.TP 7 +>0 +An error occurred. +.sp +.SH CONSEQUENCES OF ERRORS +.LP +When any error is encountered and the standard input is not a terminal +device file, \fIex\fP shall not write the file or return +to command or text input mode, and shall terminate with a non-zero +exit status. +.LP +Otherwise, when an unrecoverable error is encountered, it shall be +equivalent to a SIGHUP asynchronous event. +.LP +Otherwise, when an error is encountered, the editor shall behave as +specified in Command Line Parsing +in ex . +.LP +\fIThe following sections are informative.\fP +.SH APPLICATION USAGE +.LP +If a SIGSEGV signal is received while \fIex\fP is saving a file, the +file might not be successfully saved. +.LP +The \fBnext\fP command can accept more than one file, so usage such +as: +.sp +.RS +.nf + +\fBnext `ls [abc]*` +\fP +.fi +.RE +.LP +is valid; it would not be valid for the \fBedit\fP or \fBread\fP commands, +for example, because they expect only one file and +unspecified results occur. +.SH EXAMPLES +.LP +None. +.SH RATIONALE +.LP +The \fIex\fP/ \fIvi\fP specification is based on the historical practice +found in the 4 BSD +and System V implementations of \fIex\fP and \fIvi\fP. A freely redistributable +implementation +of \fIex\fP/ \fIvi\fP, which is tracking IEEE\ Std\ 1003.1-2001 fairly +closely, and +demonstrates the intended changes between historical implementations +and IEEE\ Std\ 1003.1-2001, may be obtained by +anonymous FTP from: +.sp +.RS +.nf + +\fBftp://ftp.rdg.opengroup.org/pub/mirrors/nvi +\fP +.fi +.RE +.LP +A \fIrestricted editor\fP (both the historical \fIred\fP utility and +modifications to \fIex\fP) were considered and rejected +for inclusion. Neither option provided the level of security that +users might expect. +.LP +It is recognized that \fIex\fP visual mode and related features would +be difficult, if not impossible, to implement +satisfactorily on a block-mode terminal, or a terminal without any +form of cursor addressing; thus, it is not a mandatory +requirement that such features should work on all terminals. It is +the intention, however, that an \fIex\fP implementation should +provide the full set of capabilities on all terminals capable of supporting +them. +.SS Options +.LP +The \fB-c\fP replacement for \fB+\fP \fIcommand\fP was inspired by +the \fB-e\fP option of \fIsed\fP. Historically, all such commands +(see \fBedit\fP and \fBnext\fP as well) were executed +from the last line of the edit buffer. This meant, for example, that +\fB"+/pattern"\fP would fail unless the \fBwrapscan\fP +option was set. IEEE\ Std\ 1003.1-2001 requires conformance to historical +practice. Historically, some implementations +restricted the \fIex\fP commands that could be listed as part of the +command line arguments. For consistency, +IEEE\ Std\ 1003.1-2001 does not permit these restrictions. +.LP +In historical implementations of the editor, the \fB-R\fP option (and +the \fBreadonly\fP edit option) only prevented +overwriting of files; appending to files was still permitted, mapping +loosely into the \fIcsh\fP \fBnoclobber\fP variable. Some +implementations, however, have not followed this semantic, and \fBreadonly\fP +does not permit appending either. +IEEE\ Std\ 1003.1-2001 follows the latter practice, believing that +it is a more obvious and intuitive meaning of +\fBreadonly\fP. +.LP +The \fB-s\fP option suppresses all interactive user feedback and is +useful for editing scripts in batch jobs. The list of +specific effects is historical practice. The terminal type "incapable +of supporting open and visual modes" has historically been +named "dumb". +.LP +The \fB-t\fP option was required because the \fIctags\fP utility appears +in +IEEE\ Std\ 1003.1-2001 and the option is available in all historical +implementations of \fIex\fP. +.LP +Historically, the \fIex\fP and \fIvi\fP utilities accepted a \fB-x\fP +option, which did +encryption based on the algorithm found in the historical \fIcrypt\fP +utility. The \fB-x\fP option for encryption, and the +associated \fIcrypt\fP utility, were omitted because the algorithm +used was not specifiable and the export control laws of some +nations make it difficult to export cryptographic technology. In addition, +it did not historically provide the level of security +that users might expect. +.SS Standard Input +.LP +An end-of-file condition is not equivalent to an end-of-file character. +A common end-of-file character, <control>-D, is +historically an \fIex\fP command. +.LP +There was no maximum line length in historical implementations of +\fIex\fP. Specifically, as it was parsed in chunks, the +addresses had a different maximum length than the filenames. Further, +the maximum line buffer size was declared as BUFSIZ, which +was different lengths on different systems. This version selected +the value of {LINE_MAX} to impose a reasonable restriction on +portable usage of \fIex\fP and to aid test suite writers in their +development of realistic tests that exercise this limit. +.SS Input Files +.LP +It was an explicit decision by the standard developers that a <newline> +be added to any file lacking one. It was believed +that this feature of \fIex\fP and \fIvi\fP was relied on by users +in order to make text files +lacking a trailing <newline> more portable. It is recognized that +this will require a user-specified option or extension for +implementations that permit \fIex\fP and \fIvi\fP to edit files of +type other than text if +such files are not otherwise identified by the system. It was agreed +that the ability to edit files of arbitrary type can be +useful, but it was not considered necessary to mandate that an \fIex\fP +or \fIvi\fP +implementation be required to handle files other than text files. +.LP +The paragraph in the INPUT FILES section, "By default, ...", is intended +to close a long-standing security problem in +\fIex\fP and \fIvi\fP; that of the "modeline" or "modelines" edit +option. This feature +allows any line in the first or last five lines of the file containing +the strings \fB"ex:"\fP or \fB"vi:"\fP (and, +apparently, \fB"ei:"\fP or \fB"vx:"\fP ) to be a line containing editor +commands, and \fIex\fP interprets all the text up to +the next \fB':'\fP or <newline> as a command. Consider the consequences, +for example, of an unsuspecting user using +\fIex\fP or \fIvi\fP as the editor when replying to a mail message +in which a line such +as: +.sp +.RS +.nf + +\fBex:! rm -rf : +\fP +.fi +.RE +.LP +appeared in the signature lines. The standard developers believed +strongly that an editor should not by default interpret any +lines of a file. Vendors are strongly urged to delete this feature +from their implementations of \fIex\fP and \fIvi\fP. +.SS Asynchronous Events +.LP +The intention of the phrase "complete write" is that the entire edit +buffer be written to stable storage. The note regarding +temporary files is intended for implementations that use temporary +files to back edit buffers unnamed by the user. +.LP +Historically, SIGQUIT was ignored by \fIex\fP, but was the equivalent +of the \fBQ\fP command in visual mode; that is, it +exited visual mode and entered \fIex\fP mode. IEEE\ Std\ 1003.1-2001 +permits, but does not require, this behavior. +Historically, SIGINT was often used by \fIvi\fP users to terminate +text input mode ( +<control>-C is often easier to enter than <ESC>). Some implementations +of \fIvi\fP +alerted the terminal on this event, and some did not. IEEE\ Std\ 1003.1-2001 +requires that SIGINT behave identically to +<ESC>, and that the terminal not be alerted. +.LP +Historically, suspending the \fIex\fP editor during text input mode +was similar to SIGINT, as completed lines were retained, +but any partial line discarded, and the editor returned to command +mode. IEEE\ Std\ 1003.1-2001 is silent on this issue; +implementations are encouraged to follow historical practice, where +possible. +.LP +Historically, the \fIvi\fP editor did not treat SIGTSTP as an asynchronous +event, and it was +therefore impossible to suspend the editor in visual text input mode. +There are two major reasons for this. The first is that +SIGTSTP is a broadcast signal on UNIX systems, and the chain of events +where the shell \fIexec\fPs an application that then \fIexec\fPs \fIvi\fP +usually caused confusion for the +terminal state if SIGTSTP was delivered to the process group in the +default manner. The second was that most implementations of the +UNIX \fIcurses\fP package are not reentrant, and the receipt of SIGTSTP +at the wrong time will cause them to crash. +IEEE\ Std\ 1003.1-2001 is silent on this issue; implementations are +encouraged to treat suspension as an asynchronous event +if possible. +.LP +Historically, modifications to the edit buffer made before SIGINT +interrupted an operation were retained; that is, anywhere from +zero to all of the lines to be modified might have been modified by +the time the SIGINT arrived. These changes were not discarded +by the arrival of SIGINT. IEEE\ Std\ 1003.1-2001 permits this behavior, +noting that the \fBundo\fP command is required to +be able to undo these partially completed commands. +.LP +The action taken for signals other than SIGINT, SIGCONT, SIGHUP, and +SIGTERM is unspecified because some implementations attempt +to save the edit buffer in a useful state when other signals are received. +.SS Standard Error +.LP +For \fIex\fP/ \fIvi\fP, diagnostic messages are those messages reported +as a result of a +failed attempt to invoke \fIex\fP or \fIvi\fP, such as invalid options +or insufficient +resources, or an abnormal termination condition. Diagnostic messages +should not be confused with the error messages generated by +inappropriate or illegal user commands. +.SS Initialization in ex and vi +.LP +If an \fIex\fP command (other than \fBcd\fP, \fBchdir\fP, or \fBsource\fP) +has a filename argument, one or both of the +alternate and current pathnames will be set. Informally, they are +set as follows: +.IP " 1." 4 +If the \fIex\fP command is one that replaces the contents of the edit +buffer, and it succeeds, the current pathname will be set +to the filename argument (the first filename argument in the case +of the \fBnext\fP command) and the alternate pathname will be +set to the previous current pathname, if there was one. +.LP +.IP " 2." 4 +In the case of the file read/write forms of the \fBread\fP and \fBwrite\fP +commands, if there is no current pathname, the +current pathname will be set to the filename argument. +.LP +.IP " 3." 4 +Otherwise, the alternate pathname will be set to the filename argument. +.LP +.LP +For example, \fB:edit foo\fP and \fB:recover foo\fP, when successful, +set the current pathname, and, if there was a previous +current pathname, the alternate pathname. The commands \fB:write\fP, +\fB!command\fP, and \fB:edit\fP set neither the current or +alternate pathnames. If the \fB:edit foo\fP command were to fail for +some reason, the alternate pathname would be set. The +\fBread\fP and \fBwrite\fP commands set the alternate pathname to +their \fIfile\fP argument, unless the current pathname is not +set, in which case they set the current pathname to their \fIfile\fP +arguments. The alternate pathname was not historically set by +the \fB:source\fP command. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. Implementations adding +commands that take filenames as arguments are encouraged to set the +alternate pathname as described here. +.LP +Historically, \fIex\fP and \fIvi\fP read the \fB.exrc\fP file in the +\fI$HOME\fP +directory twice, if the editor was executed in the \fI$HOME\fP directory. +IEEE\ Std\ 1003.1-2001 prohibits this +behavior. +.LP +Historically, the 4 BSD \fIex\fP and \fIvi\fP read the \fI$HOME\fP +and local \fB.exrc\fP +files if they were owned by the real ID of the user, or the \fBsourceany\fP +option was set, regardless of other considerations. +This was a security problem because it is possible to put normal UNIX +system commands inside a \fB.exrc\fP file. +IEEE\ Std\ 1003.1-2001 does not specify the \fBsourceany\fP option, +and historical implementations are encouraged to +delete it. +.LP +The \fB.exrc\fP files must be owned by the real ID of the user, and +not writable by anyone other than the owner. The +appropriate privileges exception is intended to permit users to acquire +special privileges, but continue to use the \fB.exrc\fP +files in their home directories. +.LP +System V Release 3.2 and later \fIvi\fP implementations added the +option \fB[no]exrc\fP. +The behavior is that local \fB.exrc\fP files are read-only if the +\fBexrc\fP option is set. The default for the \fBexrc\fP +option was off, so by default, local \fB.exrc\fP files were not read. +The problem this was intended to solve was that System V +permitted users to give away files, so there is no possible ownership +or writeability test to ensure that the file is safe. This is +still a security problem on systems where users can give away files, +but there is nothing additional that +IEEE\ Std\ 1003.1-2001 can do. The implementation-defined exception +is intended to permit groups to have local \fB.exrc\fP +files that are shared by users, by creating pseudo-users to own the +shared files. +.LP +IEEE\ Std\ 1003.1-2001 does not mention system-wide \fIex\fP and \fIvi\fP +start-up +files. While they exist in several implementations of \fIex\fP and +\fIvi\fP, they are not +present in any implementations considered historical practice by IEEE\ Std\ 1003.1-2001. +Implementations that have such +files should use them only if they are owned by the real user ID or +an appropriate user (for example, root on UNIX systems) and if +they are not writable by any user other than their owner. System-wide +start-up files should be read before the \fIEXINIT\fP +variable, \fB$HOME/.exrc\fP, or local \fB.exrc\fP files are evaluated. +.LP +Historically, any \fIex\fP command could be entered in the \fIEXINIT\fP +variable or the \fB.exrc\fP file, although ones +requiring that the edit buffer already contain lines of text generally +caused historical implementations of the editor to drop +\fBcore\fP. IEEE\ Std\ 1003.1-2001 requires that any \fIex\fP command +be permitted in the \fIEXINIT\fP variable and +\fB\&.exrc\fP files, for simplicity of specification and consistency, +although many of them will obviously fail under many +circumstances. +.LP +The initialization of the contents of the edit buffer uses the phrase +"the effect shall be" with regard to various \fIex\fP +commands. The intent of this phrase is that edit buffer contents loaded +during the initialization phase not be lost; that is, +loading the edit buffer should fail if the \fB.exrc\fP file read in +the contents of a file and did not subsequently write the edit +buffer. An additional intent of this phrase is to specify that the +initial current line and column is set as specified for the +individual \fIex\fP commands. +.LP +Historically, the \fB-t\fP option behaved as if the tag search were +a \fB+\fP \fIcommand\fP; that is, it was executed from +the last line of the file specified by the tag. This resulted in the +search failing if the pattern was a forward search pattern and +the \fBwrapscan\fP edit option was not set. IEEE\ Std\ 1003.1-2001 +does not permit this behavior, requiring that the +search for the tag pattern be performed on the entire file, and, if +not found, that the current line be set to a more reasonable +location in the file. +.LP +Historically, the empty edit buffer presented for editing when a file +was not specified by the user was unnamed. This is +permitted by IEEE\ Std\ 1003.1-2001; however, implementations are +encouraged to provide users a temporary filename for this +buffer because it permits them the use of \fIex\fP commands that use +the current pathname during temporary edit sessions. +.LP +Historically, the file specified using the \fB-t\fP option was not +part of the current argument list. This practice is +permitted by IEEE\ Std\ 1003.1-2001; however, implementations are +encouraged to include its name in the current argument +list for consistency. +.LP +Historically, the \fB-c\fP command was generally not executed until +a file that already exists was edited. +IEEE\ Std\ 1003.1-2001 requires conformance to this historical practice. +Commands that could cause the \fB-c\fP command to +be executed include the \fIex\fP commands \fBedit\fP, \fBnext\fP, +\fBrecover\fP, \fBrewind\fP, and \fBtag\fP, and the \fIvi\fP commands +<control>-^ and <control>-]. Historically, reading a file into an +edit buffer did not cause the \fB-c\fP command to be executed (even +though it might set the current pathname) with the exception +that it did cause the \fB-c\fP command to be executed if: the editor +was in \fIex\fP mode, the edit buffer had no current +pathname, the edit buffer was empty, and no read commands had yet +been attempted. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 does not permit this behavior. +.LP +Historically, the \fB-r\fP option was the same as a normal edit session +if there was no recovery information available for the +file. This allowed users to enter: +.sp +.RS +.nf + +\fBvi -r *.c +\fP +.fi +.RE +.LP +and recover whatever files were recoverable. In some implementations, +recovery was attempted only on the first file named, and +the file was not entered into the argument list; in others, recovery +was attempted for each file named. In addition, some +historical implementations ignored \fB-r\fP if \fB-t\fP was specified +or did not support command line \fIfile\fP arguments with +the \fB-t\fP option. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 disallows these special +cases, and requires that recovery be attempted the first time each +file is edited. +.LP +Historically, \fIvi\fP initialized the \fB`\fP and \fB'\fP marks, +but \fIex\fP did not. +This meant that if the first command in \fIex\fP mode was \fBvisual\fP +or if an \fIex\fP command was executed first (for +example, \fIvi\fP +10 \fIfile\fP), \fIvi\fP was entered +without the marks being initialized. Because the standard developers +believed the marks to be generally useful, and for consistency +and simplicity of specification, IEEE\ Std\ 1003.1-2001 requires that +they always be initialized if in open or visual mode, +or if in \fIex\fP mode and the edit buffer is not empty. Not initializing +it in \fIex\fP mode if the edit buffer is empty is +historical practice; however, it has always been possible to set (and +use) marks in empty edit buffers in open and visual mode edit +sessions. +.SS Addressing +.LP +Historically, \fIex\fP and \fIvi\fP accepted the additional addressing +forms \fB'\\/'\fP +and \fB'\\?'\fP . They were equivalent to \fB"//"\fP and \fB"??"\fP, +respectively. They are not required by +IEEE\ Std\ 1003.1-2001, mostly because nobody can remember whether +they ever did anything different historically. +.LP +Historically, \fIex\fP and \fIvi\fP permitted an address of zero for +several commands, and +permitted the \fB%\fP address in empty files for others. For consistency, +IEEE\ Std\ 1003.1-2001 requires support for the +former in the few commands where it makes sense, and disallows it +otherwise. In addition, because IEEE\ Std\ 1003.1-2001 +requires that \fB%\fP be logically equivalent to \fB"1,$"\fP, it +is also supported where it makes sense and disallowed +otherwise. +.LP +Historically, the \fB%\fP address could not be followed by further +addresses. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 requires that additional addresses be supported. +.LP +All of the following are valid \fIaddresses\fP: +.TP 7 +\fB+++\fP +Three lines after the current line. +.TP 7 +\fB/\fP\fIre\fP\fB/-\fP +One line before the next occurrence of \fIre\fP. +.TP 7 +\fB-2\fP +Two lines before the current line. +.TP 7 +\fB3\ ----\ 2\fP +Line one (note intermediate negative address). +.TP 7 +\fB1\ 2\ 3\fP +Line six. +.sp +.LP +Any number of addresses can be provided to commands taking addresses; +for example, \fB"1,2,3,4,5p"\fP prints lines 4 and 5, +because two is the greatest valid number of addresses accepted by +the \fBprint\fP command. This, in combination with the semicolon +delimiter, permits users to create commands based on ordered patterns +in the file. For example, the command \fB3;/foo/;+2print\fP +will display the first line after line 3 that contains the pattern +\fIfoo\fP, plus the next two lines. Note that the address +\fB3;\fP must be evaluated before being discarded because the search +origin for the \fB/foo/\fP command depends on this. +.LP +Historically, values could be added to addresses by including them +after one or more <blank>s; for example, +\fB3\ -\ 5p\fP wrote the seventh line of the file, and \fB/foo/\ 5\fP +was the same as \fB/foo/+5\fP. However, only +absolute values could be added; for example, \fB5\ /foo/\fP was an +error. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. Address offsets are separately specified from +addresses because they could historically be provided to +visual mode search commands. +.LP +Historically, any missing addresses defaulted to the current line. +This was true for leading and trailing comma-delimited +addresses, and for trailing semicolon-delimited addresses. For consistency, +IEEE\ Std\ 1003.1-2001 requires it for leading +semicolon addresses as well. +.LP +Historically, \fIex\fP and \fIvi\fP accepted the \fB'^'\fP character +as both an address +and as a flag offset for commands. In both cases it was identical +to the \fB'-'\fP character. IEEE\ Std\ 1003.1-2001 +does not require or prohibit this behavior. +.LP +Historically, the enhancements to basic regular expressions could +be used in addressing; for example, \fB'~'\fP, +\fB'\\<'\fP, and \fB'\\>'\fP . IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice; that is, that +regular expression usage be consistent, and that regular expression +enhancements be supported wherever regular expressions are +used. +.SS Command Line Parsing in ex +.LP +Historical \fIex\fP command parsing was even more complex than that +described here. IEEE\ Std\ 1003.1-2001 requires the +subset of the command parsing that the standard developers believed +was documented and that users could reasonably be expected to +use in a portable fashion, and that was historically consistent between +implementations. (The discarded functionality is obscure, +at best.) Historical implementations will require changes in order +to comply with IEEE\ Std\ 1003.1-2001; however, users +are not expected to notice any of these changes. Most of the complexity +in \fIex\fP parsing is to handle three special termination +cases: +.IP " 1." 4 +The \fB!\fP, \fBglobal\fP, \fBv\fP, and the filter versions of the +\fBread\fP and \fBwrite\fP commands are delimited by +<newline>s (they can contain vertical-line characters that are usually +shell pipes). +.LP +.IP " 2." 4 +The \fBex\fP, \fBedit\fP, \fBnext\fP, and \fBvisual\fP in open and +visual mode commands all take \fIex\fP commands, +optionally containing vertical-line characters, as their first arguments. +.LP +.IP " 3." 4 +The \fBs\fP command takes a regular expression as its first argument, +and uses the delimiting characters to delimit the +command. +.LP +.LP +Historically, vertical-line characters in the \fB+\fP \fIcommand\fP +argument of the \fBex\fP, \fBedit\fP, \fBnext\fP, +\fBvi\fP, and \fBvisual\fP commands, and in the \fIpattern\fP and +\fIreplacement\fP parts of the \fBs\fP command, did not +delimit the command, and in the filter cases for \fBread\fP and \fBwrite\fP, +and the \fB!\fP, \fBglobal\fP, and \fBv\fP +commands, they did not delimit the command at all. For example, the +following commands are all valid: +.sp +.RS +.nf + +\fB:\fP\fBedit +25 | s/abc/ABC/ file.c +\fP\fB:\fP\fBs/ | /PIPE/ +\fP\fB:\fP\fBread !spell % | columnate +\fP\fB:\fP\fBglobal/pattern/p | l +\fP\fB:\fP\fBs/a/b/ | s/c/d | set +\fP +.fi +.RE +.LP +Historically, empty or <blank> filled lines in \fB.exrc\fP files and +\fBsource\fPd files (as well as \fIEXINIT\fP +variables and \fIex\fP command scripts) were treated as default commands; +that is, \fBprint\fP commands. +IEEE\ Std\ 1003.1-2001 specifically requires that they be ignored +when encountered in \fB.exrc\fP and \fBsource\fPd files +to eliminate a common source of new user error. +.LP +Historically, \fIex\fP commands with multiple adjacent (or <blank>-separated) +vertical lines were handled oddly when +executed from \fIex\fP mode. For example, the command \fB|||\fP <carriage-return>, +when the cursor was on line 1, displayed +lines 2, 3, and 5 of the file. In addition, the command \fB|\fP would +only display the line after the next line, instead of the +next two lines. The former worked more logically when executed from +\fIvi\fP mode, and +displayed lines 2, 3, and 4. IEEE\ Std\ 1003.1-2001 requires the \fIvi\fP +behavior; +that is, a single default command and line number increment for each +command separator, and trailing <newline>s after +vertical-line separators are discarded. +.LP +Historically, \fIex\fP permitted a single extra colon as a leading +command character; for example, \fB:g/pattern/:p\fP was a +valid command. IEEE\ Std\ 1003.1-2001 generalizes this to require +that any number of leading colon characters be +stripped. +.LP +Historically, any prefix of the \fBdelete\fP command could be followed +without intervening <blank>s by a flag character +because in the command \fBd\ p\fP, \fIp\fP is interpreted as the buffer +\fIp\fP. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice. +.LP +Historically, the \fBk\fP command could be followed by the mark name +without intervening <blank>s. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice. +.LP +Historically, the \fBs\fP command could be immediately followed by +flag and option characters; for example, +\fBs/e/E/|s|sgc3p\fP was a valid command. However, flag characters +could not stand alone; for example, the commands \fBsp\fP and +\fBs\ l\fP would fail, while the command \fBsgp\fP and \fBs\ gl\fP +would succeed. (Obviously, the \fB'#'\fP flag +character was used as a delimiter character if it followed the command.) +Another issue was that option characters had to precede +flag characters even when the command was fully specified; for example, +the command \fBs/e/E/pg\fP would fail, while the command +\fBs/e/E/gp\fP would succeed. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. +.LP +Historically, the first command name that had a prefix matching the +input from the user was the executed command; for example, +\fBve\fP, \fBver\fP, and \fBvers\fP all executed the \fBversion\fP +command. Commands were in a specific order, however, so that +\fBa\fP matched \fBappend\fP, not \fBabbreviate\fP. IEEE\ Std\ 1003.1-2001 +requires conformance to historical practice. +The restriction on command search order for implementations with extensions +is to avoid the addition of commands such that the +historical prefixes would fail to work portably. +.LP +Historical implementations of \fIex\fP and \fIvi\fP did not correctly +handle multiple +\fIex\fP commands, separated by vertical-line characters, that entered +or exited visual mode or the editor. Because +implementations of \fIvi\fP exist that do not exhibit this failure +mode, +IEEE\ Std\ 1003.1-2001 does not permit it. +.LP +The requirement that alphabetic command names consist of all following +alphabetic characters up to the next non-alphabetic +character means that alphabetic command names must be separated from +their arguments by one or more non-alphabetic characters, +normally a <blank> or \fB'!'\fP character, except as specified for +the exceptions, the \fBdelete\fP, \fBk\fP, and +\fBs\fP commands. +.LP +Historically, the repeated execution of the \fIex\fP default \fBprint\fP +commands ( <control>-D, \fIeof\fP, +<newline>, <carriage-return>) erased any prompting character and displayed +the next lines without scrolling the +terminal; that is, immediately below any previously displayed lines. +This provided a cleaner presentation of the lines in the file +for the user. IEEE\ Std\ 1003.1-2001 does not require this behavior +because it may be impossible in some situations; +however, implementations are strongly encouraged to provide this semantic +if possible. +.LP +Historically, it was possible to change files in the middle of a command, +and have the rest of the command executed in the new +file; for example: +.sp +.RS +.nf + +\fB:edit +25 file.c | s/abc/ABC/ | 1 +\fP +.fi +.RE +.LP +was a valid command, and the substitution was attempted in the newly +edited file. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice. The following commands are examples +that exercise the \fIex\fP parser: +.sp +.RS +.nf + +\fBecho 'foo | bar' > file1; echo 'foo/bar' > file2; +vi +:edit +1 | s/|/PIPE/ | w file1 | e file2 | 1 | s/\\//SLASH/ | wq +\fP +.fi +.RE +.LP +Historically, there was no protection in editor implementations to +avoid \fIex\fP \fBglobal\fP, \fBv\fP, \fB@\fP, or +\fB*\fP commands changing edit buffers during execution of their associated +commands. Because this would almost invariably result +in catastrophic failure of the editor, and implementations exist that +do exhibit these problems, IEEE\ Std\ 1003.1-2001 +requires that changing the edit buffer during a \fBglobal\fP or \fBv\fP +command, or during a \fB@\fP or \fB*\fP command for +which there will be more than a single execution, be an error. Implementations +supporting multiple edit buffers simultaneously are +strongly encouraged to apply the same semantics to switching between +buffers as well. +.LP +The \fIex\fP command quoting required by IEEE\ Std\ 1003.1-2001 is +a superset of the quoting in historical +implementations of the editor. For example, it was not historically +possible to escape a <blank> in a filename; for example, +\fB:edit\ foo\\\\\\\ bar\fP would report that too many filenames had +been entered for the edit command, and there was no +method of escaping a <blank> in the first argument of an \fBedit\fP, +\fBex\fP, \fBnext\fP, or \fBvisual\fP command at +all. IEEE\ Std\ 1003.1-2001 extends historical practice, requiring +that quoting behavior be made consistent across all +\fIex\fP commands, except for the \fBmap\fP, \fBunmap\fP, \fBabbreviate\fP, +and \fBunabbreviate\fP commands, which +historically used <control>-V instead of backslashes for quoting. +For those four commands, IEEE\ Std\ 1003.1-2001 +requires conformance to historical practice. +.LP +Backslash quoting in \fIex\fP is non-intuitive. Backslash escapes +are ignored unless they escape a special character; for +example, when performing \fIfile\fP argument expansion, the string +\fB"\\\\%"\fP is equivalent to \fB'\\%'\fP, not +\fB"\\<\fP\fIcurrent\ pathname\fP\fB>"\fP. This can be confusing for +users because backslash is usually one of the +characters that causes shell expansion to be performed, and therefore +shell quoting rules must be taken into consideration. +Generally, quoting characters are only considered if they escape a +special character, and a quoting character must be provided for +each layer of parsing for which the character is special. As another +example, only a single backslash is necessary for the +\fB'\\l'\fP sequence in substitute replacement patterns, because the +character \fB'l'\fP is not special to any parsing layer +above it. +.LP +<control>-V quoting in \fIex\fP is slightly different from backslash +quoting. In the four commands where +<control>-V quoting applies ( \fBabbreviate\fP, \fBunabbreviate\fP, +\fBmap\fP, and \fBunmap\fP), any character may be +escaped by a <control>-V whether it would have a special meaning or +not. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. +.LP +Historical implementations of the editor did not require delimiters +within character classes to be escaped; for example, the +command \fB:s/[/]//\fP on the string \fB"xxx/yyy"\fP would delete +the \fB'/'\fP from the string. +IEEE\ Std\ 1003.1-2001 disallows this historical practice for consistency +and because it places a large burden on +implementations by requiring that knowledge of regular expressions +be built into the editor parser. +.LP +Historically, quoting <newline>s in \fIex\fP commands was handled +inconsistently. In most cases, the <newline> +always terminated the command, regardless of any preceding escape +character, because backslash characters did not escape +<newline>s for most \fIex\fP commands. However, some \fIex\fP commands +(for example, \fBs\fP, \fBmap\fP, and +\fBabbreviation\fP) permitted <newline>s to be escaped (although in +the case of \fBmap\fP and \fBabbreviation\fP, +<control>-V characters escaped them instead of backslashes). This +was true in not only the command line, but also +\fB\&.exrc\fP and \fBsource\fPd files. For example, the command: +.sp +.RS +.nf + +\fBmap = foo<control-V><newline>bar +\fP +.fi +.RE +.LP +would succeed, although it was sometimes difficult to get the <control>-V +and the inserted <newline> passed to the +\fIex\fP parser. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 requires that it be possible to +escape <newline>s in \fIex\fP commands at all times, using backslashes +for most \fIex\fP commands, and using +<control>-V characters for the \fBmap\fP and \fBabbreviation\fP commands. +For example, the command \fBprint\fP +<newline> \fBlist\fP is required to be parsed as the single command +\fBprint\fP <newline> \fBlist\fP. While this +differs from historical practice, IEEE\ Std\ 1003.1-2001 developers +believed it unlikely that any script or user depended +on the historical behavior. +.LP +Historically, an error in a command specified using the \fB-c\fP option +did not cause the rest of the \fB-c\fP commands to be +discarded. IEEE\ Std\ 1003.1-2001 disallows this for consistency with +mapped keys, the \fB@\fP, \fBglobal\fP, +\fBsource\fP, and \fBv\fP commands, the \fIEXINIT\fP environment variable, +and the \fB.exrc\fP files. +.SS Input Editing in ex +.LP +One of the common uses of the historical \fIex\fP editor is over slow +network connections. Editors that run in canonical mode +can require far less traffic to and from, and far less processing +on, the host machine, as well as more easily supporting +block-mode terminals. For these reasons, IEEE\ Std\ 1003.1-2001 requires +that \fIex\fP be implemented using canonical mode +input processing, as was done historically. +.LP +IEEE\ Std\ 1003.1-2001 does not require the historical 4 BSD input +editing characters "word erase" or "literal +next". For this reason, it is unspecified how they are handled by +\fIex\fP, although they must have the required effect. +Implementations that resolve them after the line has been ended using +a <newline> or <control>-M character, and +implementations that rely on the underlying system terminal support +for this processing, are both conforming. Implementations are +strongly urged to use the underlying system functionality, if at all +possible, for compatibility with other system text input +interfaces. +.LP +Historically, when the \fIeof\fP character was used to decrement the +\fBautoindent\fP level, the cursor moved to display the +new end of the \fBautoindent\fP characters, but did not move the cursor +to a new line, nor did it erase the <control>-D +character from the line. IEEE\ Std\ 1003.1-2001 does not specify that +the cursor remain on the same line or that the rest +of the line is erased; however, implementations are strongly encouraged +to provide the best possible user interface; that is, the +cursor should remain on the same line, and any <control>-D character +on the line should be erased. +.LP +IEEE\ Std\ 1003.1-2001 does not require the historical 4 BSD input +editing character "reprint", traditionally +<control>-R, which redisplayed the current input from the user. For +this reason, and because the functionality cannot be +implemented after the line has been terminated by the user, IEEE\ Std\ 1003.1-2001 +makes no requirements about this +functionality. Implementations are strongly urged to make this historical +functionality available, if possible. +.LP +Historically, <control>-Q did not perform a literal next function +in \fIex\fP, as it did in \fIvi\fP. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice to avoid breaking +historical \fIex\fP scripts and \fB.exrc\fP files. +.SS eof +.LP +Whether the \fIeof\fP character immediately modifies the \fBautoindent\fP +characters in the prompt is left unspecified so that +implementations can conform in the presence of systems that do not +support this functionality. Implementations are encouraged to +modify the line and redisplay it immediately, if possible. +.LP +The specification of the handling of the \fIeof\fP character differs +from historical practice only in that \fIeof\fP +characters are not discarded if they follow normal characters in the +text input. Historically, they were always discarded. +.SS Command Descriptions in ex +.LP +Historically, several commands (for example, \fBglobal\fP, \fBv\fP, +\fBvisual\fP, \fBs\fP, \fBwrite\fP, \fBwq\fP, +\fByank\fP, \fB!\fP, \fB<\fP, \fB>\fP, \fB&\fP, and \fB~\fP) were +executable in empty files (that is, the +default address(es) were 0), or permitted explicit addresses of 0 +(for example, 0 was a valid address, or 0,0 was a valid range). +Addresses of 0, or command execution in an empty file, make sense +only for commands that add new text to the edit buffer or write +commands (because users may wish to write empty files). IEEE\ Std\ 1003.1-2001 +requires this behavior for such commands and +disallows it otherwise, for consistency and simplicity of specification. +.LP +A count to an \fIex\fP command has been historically corrected to +be no greater than the last line in a file; for example, in a +five-line file, the command \fB1,6print\fP would fail, but the command +\fB1print300\fP would succeed. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice. +.LP +Historically, the use of flags in \fIex\fP commands could be obscure. +General historical practice was as described by +IEEE\ Std\ 1003.1-2001, but there were some special cases. For instance, +the \fBlist\fP, \fBnumber\fP, and \fBprint\fP +commands ignored trailing address offsets; for example, \fB3p\ +++#\fP +would display line 3, and 3 would be the current line +after the execution of the command. The \fBopen\fP and \fBvisual\fP +commands ignored both the trailing offsets and the trailing +flags. Also, flags specified to the \fBopen\fP and \fBvisual\fP commands +interacted badly with the \fBlist\fP edit option, and +setting and then unsetting it during the open/visual session would +cause \fIvi\fP to stop +displaying lines in the specified format. For consistency and simplicity +of specification, IEEE\ Std\ 1003.1-2001 does not +permit any of these exceptions to the general rule. +.LP +IEEE\ Std\ 1003.1-2001 uses the word \fIcopy\fP in several places +when discussing buffers. This is not intended to +imply implementation. +.LP +Historically, \fIex\fP users could not specify numeric buffers because +of the ambiguity this would cause; for example, in the +command \fB3\ delete\ 2\fP, it is unclear whether 2 is a buffer name +or a \fIcount\fP. IEEE\ Std\ 1003.1-2001 +requires conformance to historical practice by default, but does not +preclude extensions. +.LP +Historically, the contents of the unnamed buffer were frequently discarded +after commands that did not explicitly affect it; for +example, when using the \fBedit\fP command to switch files. For consistency +and simplicity of specification, +IEEE\ Std\ 1003.1-2001 does not permit this behavior. +.LP +The \fIex\fP utility did not historically have access to the numeric +buffers, and, furthermore, deleting lines in \fIex\fP did +not modify their contents. For example, if, after doing a delete in +\fIvi\fP, the user switched +to \fIex\fP, did another delete, and then switched back to \fIvi\fP, +the contents of the +numeric buffers would not have changed. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice. Numeric buffers +are described in the \fIex\fP utility in order to confine the description +of buffers to a single location in +IEEE\ Std\ 1003.1-2001. +.LP +The metacharacters that trigger shell expansion in \fIfile\fP arguments +match historical practice, as does the method for doing +shell expansion. Implementations wishing to provide users with the +flexibility to alter the set of metacharacters are encouraged to +provide a \fBshellmeta\fP string edit option. +.LP +Historically, \fIex\fP commands executed from \fIvi\fP refreshed the +screen when it did not +strictly need to do so; for example, \fB:!date\ >\ /dev/null\fP does +not require a screen refresh because the output of +the UNIX \fIdate\fP command requires only a single line of the screen. +IEEE\ Std\ 1003.1-2001 requires that the screen be refreshed if it +has been overwritten, but makes no requirements as to +how an implementation should make that determination. Implementations +may prompt and refresh the screen regardless. +.SS Abbreviate +.LP +Historical practice was that characters that were entered as part +of an abbreviation replacement were subject to \fBmap\fP +expansions, the \fBshowmatch\fP edit option, further abbreviation +expansions, and so on; that is, they were logically pushed onto +the terminal input queue, and were not a simple replacement. IEEE\ Std\ 1003.1-2001 +requires conformance to historical +practice. Historical practice was that whenever a non-word character +(that had not been escaped by a <control>-V) was entered +after a word character, \fIvi\fP would check for abbreviations. The +check was based on the type +of the character entered before the word character of the word/non-word +pair that triggered the check. The word character of the +word/non-word pair that triggered the check and all characters entered +before the trigger pair that were of that type were included +in the check, with the exception of <blank>s, which always delimited +the abbreviation. +.LP +This means that, for the abbreviation to work, the \fIlhs\fP must +end with a word character, there can be no transitions from +word to non-word characters (or \fIvice versa\fP) other than between +the last and next-to-last characters in the \fIlhs\fP, and +there can be no <blank>s in the \fIlhs\fP. In addition, because of +the historical quoting rules, it was impossible to enter +a literal <control>-V in the \fIlhs\fP. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice. +Historical implementations did not inform users when abbreviations +that could never be used were entered; implementations are +strongly encouraged to do so. +.LP +For example, the following abbreviations will work: +.sp +.RS +.nf + +\fB:ab (p REPLACE +:ab p REPLACE +:ab ((p REPLACE +\fP +.fi +.RE +.LP +The following abbreviations will not work: +.sp +.RS +.nf + +\fB:ab ( REPLACE +:ab (pp REPLACE +\fP +.fi +.RE +.LP +Historical practice is that words on the \fIvi\fP colon command line +were subject to +abbreviation expansion, including the arguments to the \fBabbrev\fP +(and more interestingly) the \fBunabbrev\fP command. Because +there are implementations that do not do abbreviation expansion for +the first argument to those commands, this is permitted, but +not required, by IEEE\ Std\ 1003.1-2001. However, the following sequence: +.sp +.RS +.nf + +\fB:ab foo bar +:ab foo baz +\fP +.fi +.RE +.LP +resulted in the addition of an abbreviation of \fB"baz"\fP for the +string \fB"bar"\fP in historical \fIex\fP/ \fIvi\fP, and the sequence: +.sp +.RS +.nf + +\fB:ab foo1 bar +:ab foo2 bar +:unabbreviate foo2 +\fP +.fi +.RE +.LP +deleted the abbreviation \fB"foo1"\fP, not \fB"foo2"\fP . These behaviors +are not permitted by +IEEE\ Std\ 1003.1-2001 because they clearly violate the expectations +of the user. +.LP +It was historical practice that <control>-V, not backslash, characters +be interpreted as escaping subsequent characters in +the \fBabbreviate\fP command. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice; however, it should be +noted that an abbreviation containing a <blank> will never work. +.SS Append +.LP +Historically, any text following a vertical-line command separator +after an \fBappend\fP, \fBchange\fP, or \fBinsert\fP +command became part of the insert text. For example, in the command: +.sp +.RS +.nf + +\fB:g/pattern/append|stuff1 +\fP +.fi +.RE +.LP +a line containing the text \fB"stuff1"\fP would be appended to each +line matching pattern. It was also historically valid to +enter: +.sp +.RS +.nf + +\fB:append|stuff1 +stuff2 +\&. +\fP +.fi +.RE +.LP +and the text on the \fIex\fP command line would be appended along +with the text inserted after it. There was an historical bug, +however, that the user had to enter two terminating lines (the \fB'.'\fP +lines) to terminate text input mode in this case. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice, +but disallows the historical need for multiple +terminating lines. +.SS Change +.LP +See the RATIONALE for the \fBappend\fP command. Historical practice +for cursor positioning after the change command when no +text is input, is as described in IEEE\ Std\ 1003.1-2001. However, +one System V implementation is known to have been +modified such that the cursor is positioned on the first address specified, +and not on the line before the first address. +IEEE\ Std\ 1003.1-2001 disallows this modification for consistency. +.LP +Historically, the \fBchange\fP command did not support buffer arguments, +although some implementations allow the specification +of an optional buffer. This behavior is neither required nor disallowed +by IEEE\ Std\ 1003.1-2001. +.SS Change Directory +.LP +A common extension in \fIex\fP implementations is to use the elements +of a \fBcdpath\fP edit option as prefix directories for +\fIpath\fP arguments to \fBchdir\fP that are relative pathnames and +that do not have \fB'.'\fP or \fB".."\fP as their first +component. Elements in the \fBcdpath\fP edit option are colon-separated. +The initial value of the \fBcdpath\fP edit option is the +value of the shell \fICDPATH\fP environment variable. This feature +was not included in IEEE\ Std\ 1003.1-2001 because it +does not exist in any of the implementations considered historical +practice. +.SS Copy +.LP +Historical implementations of \fIex\fP permitted copies to lines inside +of the specified range; for example, \fB:2,5copy3\fP +was a valid command. IEEE\ Std\ 1003.1-2001 requires conformance to +historical practice. +.SS Delete +.LP +IEEE\ Std\ 1003.1-2001 requires support for the historical parsing +of a \fBdelete\fP command followed by flags, without +any intervening <blank>s. For example: +.TP 7 +\fB1dp\fP +Deletes the first line and prints the line that was second. +.TP 7 +\fB1delep\fP +As for \fB1dp\fP. +.TP 7 +\fB1d\fP +Deletes the first line, saving it in buffer \fIp\fP. +.TP 7 +\fB1d\ p1l\fP +(Pee-one-ell.) Deletes the first line, saving it in buffer \fIp\fP, +and listing the line that was second. +.sp +.SS Edit +.LP +Historically, any \fIex\fP command could be entered as a \fB+\fP \fIcommand\fP +argument to the \fBedit\fP command, although +some (for example, \fBinsert\fP and \fBappend\fP) were known to confuse +historical implementations. For consistency and +simplicity of specification, IEEE\ Std\ 1003.1-2001 requires that +any command be supported as an argument to the +\fBedit\fP command. +.LP +Historically, the command argument was executed with the current line +set to the last line of the file, regardless of whether +the \fBedit\fP command was executed from visual mode or not. IEEE\ Std\ 1003.1-2001 +requires conformance to historical +practice. +.LP +Historically, the \fB+\fP \fIcommand\fP specified to the \fBedit\fP +and \fBnext\fP commands was delimited by the first +<blank>, and there was no way to quote them. For consistency, IEEE\ Std\ 1003.1-2001 +requires that the usual +\fIex\fP backslash quoting be provided. +.LP +Historically, specifying the \fB+\fP \fIcommand\fP argument to the +edit command required a filename to be specified as well; +for example, \fB:edit\ +100\fP would always fail. For consistency +and simplicity of specification, +IEEE\ Std\ 1003.1-2001 does not permit this usage to fail for that +reason. +.LP +Historically, only the cursor position of the last file edited was +remembered by the editor. IEEE\ Std\ 1003.1-2001 +requires that this be supported; however, implementations are permitted +to remember and restore the cursor position for any file +previously edited. +.SS File +.LP +Historical versions of the \fIex\fP editor \fBfile\fP command displayed +a current line and number of lines in the edit buffer +of 0 when the file was empty, while the \fIvi\fP <control>-G command +displayed a current +line and number of lines in the edit buffer of 1 in the same situation. +IEEE\ Std\ 1003.1-2001 does not permit this +discrepancy, instead requiring that a message be displayed indicating +that the file is empty. +.SS Global +.LP +The two-pass operation of the \fBglobal\fP and \fBv\fP commands is +not intended to imply implementation, only the required +result of the operation. +.LP +The current line and column are set as specified for the individual +\fIex\fP commands. This requirement is cumulative; that is, +the current line and column must track across all the commands executed +by the \fBglobal\fP or \fBv\fP commands. +.SS Insert +.LP +See the RATIONALE for the \fBappend\fP command. +.LP +Historically, \fBinsert\fP could not be used with an address of zero; +that is, not when the edit buffer was empty. +IEEE\ Std\ 1003.1-2001 requires that this command behave consistently +with the \fBappend\fP command. +.SS Join +.LP +The action of the \fBjoin\fP command in relation to the special characters +is only defined for the POSIX locale because the +correct amount of white space after a period varies; in Japanese none +is required, in French only a single space, and so on. +.SS List +.LP +The historical output of the \fBlist\fP command was potentially ambiguous. +The standard developers believed correcting this to +be more important than adhering to historical practice, and IEEE\ Std\ 1003.1-2001 +requires unambiguous output. +.SS Map +.LP +Historically, command mode maps only applied to command names; for +example, if the character \fB'x'\fP was mapped to +\fB'y'\fP, the command \fBfx\fP searched for the \fB'x'\fP character, +not the \fB'y'\fP character. +IEEE\ Std\ 1003.1-2001 requires this behavior. Historically, entering +<control>-V as the first character of a \fIvi\fP command was an error. +Several implementations have extended the semantics of \fIvi\fP such +that <control>-V means that the subsequent command character is not +mapped. This is +permitted, but not required, by IEEE\ Std\ 1003.1-2001. Regardless, +using <control>-V to escape the second or later +character in a sequence of characters that might match a \fBmap\fP +command, or any character in text input mode, is historical +practice, and stops the entered keys from matching a map. IEEE\ Std\ 1003.1-2001 +requires conformance to historical +practice. +.LP +Historical implementations permitted digits to be used as a \fBmap\fP +command \fIlhs\fP, but then ignored the map. +IEEE\ Std\ 1003.1-2001 requires that the mapped digits not be ignored. +.LP +The historical implementation of the \fBmap\fP command did not permit +\fBmap\fP commands that were more than a single +character in length if the first character was printable. This behavior +is permitted, but not required, by +IEEE\ Std\ 1003.1-2001. +.LP +Historically, mapped characters were remapped unless the \fBremap\fP +edit option was not set, or the prefix of the mapped +characters matched the mapping characters; for example, in the \fBmap\fP: +.sp +.RS +.nf + +\fB:map ab abcd +\fP +.fi +.RE +.LP +the characters \fB"ab"\fP were used as is and were not remapped, but +the characters \fB"cd"\fP were mapped if appropriate. +This can cause infinite loops in the \fIvi\fP mapping mechanisms. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice, +and that such loops be interruptible. +.LP +Text input maps had the same problems with expanding the \fIlhs\fP +for the \fIex\fP \fBmap!\fP and \fBunmap!\fP command as +did the \fIex\fP \fBabbreviate\fP and \fBunabbreviate\fP commands. +See the RATIONALE for the \fIex\fP \fBabbreviate\fP +command. IEEE\ Std\ 1003.1-2001 requires similar modification of some +historical practice for the \fBmap\fP and +\fBunmap\fP commands, as described for the \fBabbreviate\fP and \fBunabbreviate\fP +commands. +.LP +Historically, \fBmap\fPs that were subsets of other \fBmap\fPs behaved +differently depending on the order in which they were +defined. For example: +.sp +.RS +.nf + +\fB:map! ab short +:map! abc long +\fP +.fi +.RE +.LP +would always translate the characters \fB"ab"\fP to \fB"short"\fP, +regardless of how fast the characters \fB"abc"\fP +were entered. If the entry order was reversed: +.sp +.RS +.nf + +\fB:map! abc long +:map! ab short +\fP +.fi +.RE +.LP +the characters \fB"ab"\fP would cause the editor to pause, waiting +for the completing \fB'c'\fP character, and the +characters might never be mapped to \fB"short"\fP . For consistency +and simplicity of specification, +IEEE\ Std\ 1003.1-2001 requires that the shortest match be used at +all times. +.LP +The length of time the editor spends waiting for the characters to +complete the \fIlhs\fP is unspecified because the timing +capabilities of systems are often inexact and variable, and it may +depend on other factors such as the speed of the connection. The +time should be long enough for the user to be able to complete the +sequence, but not long enough for the user to have to wait. Some +implementations of \fIvi\fP have added a \fBkeytime\fP option, which +permits users to set the +number of 0,1 seconds the editor waits for the completing characters. +Because mapped terminal function and cursor keys tend to +start with an <ESC> character, and <ESC> is the key ending \fIvi\fP +text input +mode, \fBmap\fPs starting with <ESC> characters are generally exempted +from this timeout period, or, at least timed out +differently. +.SS Mark +.LP +Historically, users were able to set the "previous context" marks +explicitly. In addition, the \fIex\fP commands \fB"\fP +and \fB'`\fP and the \fIvi\fP commands \fB"\fP, \fB``\fP, \fB`'\fP, +and \fB'`\fP all +referred to the same mark. In addition, the previous context marks +were not set if the command, with which the address setting the +mark was associated, failed. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. Historically, if marked +lines were deleted, the mark was also deleted, but would reappear +if the change was undone. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice. +.LP +The description of the special events that set the \fB`\fP and \fB'\fP +marks matches historical practice. For example, +historically the command \fB/a/,/b/\fP did not set the \fB`\fP and +\fB'\fP marks, but the command \fB/a/,/b/delete\fP did. +.SS Next +.LP +Historically, any \fIex\fP command could be entered as a \fB+\fP \fIcommand\fP +argument to the \fBnext\fP command, although +some (for example, \fBinsert\fP and \fBappend\fP) were known to confuse +historical implementations. +IEEE\ Std\ 1003.1-2001 requires that any command be permitted and +that it behave as specified. The \fBnext\fP command can +accept more than one file, so usage such as: +.sp +.RS +.nf + +\fBnext `ls [abc] ` +\fP +.fi +.RE +.LP +is valid; it need not be valid for the \fBedit\fP or \fBread\fP commands, +for example, because they expect only one +filename. +.LP +Historically, the \fBnext\fP command behaved differently from the +\fB:rewind\fP command in that it ignored the force flag if +the \fBautowrite\fP flag was set. For consistency, IEEE\ Std\ 1003.1-2001 +does not permit this behavior. +.LP +Historically, the \fBnext\fP command positioned the cursor as if the +file had never been edited before, regardless. +IEEE\ Std\ 1003.1-2001 does not permit this behavior, for consistency +with the \fBedit\fP command. +.LP +Implementations wanting to provide a counterpart to the \fBnext\fP +command that edited the previous file have used the command +\fBprev[ious],\fP which takes no \fIfile\fP argument. IEEE\ Std\ 1003.1-2001 +does not require this command. +.SS Open +.LP +Historically, the \fBopen\fP command would fail if the \fBopen\fP +edit option was not set. IEEE\ Std\ 1003.1-2001 does +not mention the \fBopen\fP edit option and does not require this behavior. +Some historical implementations do not permit entering +open mode from open or visual mode, only from \fIex\fP mode. For consistency, +IEEE\ Std\ 1003.1-2001 does not permit this +behavior. +.LP +Historically, entering open mode from the command line (that is, \fIvi\fP +\fB+open\fP) +resulted in anomalous behaviors; for example, the \fIex\fP file and +\fIset\fP +commands, and the \fIvi\fP command <control>-G did not work. For consistency, +IEEE\ Std\ 1003.1-2001 does not permit this behavior. +.LP +Historically, the \fBopen\fP command only permitted \fB'/'\fP characters +to be used as the search pattern delimiter. For +consistency, IEEE\ Std\ 1003.1-2001 requires that the search delimiters +used by the \fBs\fP, \fBglobal\fP, and \fBv\fP +commands be accepted as well. +.SS Preserve +.LP +The \fBpreserve\fP command does not historically cause the file to +be considered unmodified for the purposes of future commands +that may exit the editor. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. +.LP +Historical documentation stated that mail was not sent to the user +when preserve was executed; however, historical +implementations did send mail in this case. IEEE\ Std\ 1003.1-2001 +requires conformance to the historical +implementations. +.SS Print +.LP +The writing of NUL by the \fBprint\fP command is not specified as +a special case because the standard developers did not want +to require \fIex\fP to support NUL characters. Historically, characters +were displayed using the ARPA standard mappings, which are +as follows: +.IP " 1." 4 +Printable characters are left alone. +.LP +.IP " 2." 4 +Control characters less than \\177 are represented as \fB'^'\fP followed +by the character offset from the \fB'@'\fP +character in the ASCII map; for example, \\007 is represented as \fB'^G'\fP +\&. +.LP +.IP " 3." 4 +\\177 is represented as \fB'^'\fP followed by \fB'?'\fP . +.LP +.LP +The display of characters having their eighth bit set was less standard. +Existing implementations use hex (0x00), octal (\\000), +and a meta-bit display. (The latter displayed bytes that had their +eighth bit set as the two characters \fB"M-"\fP followed by +the seven-bit display as described above.) The latter probably has +the best claim to historical practice because it was used for +the \fB-v\fP option of 4 BSD and 4 BSD-derived versions of the \fIcat\fP +utility since +1980. +.LP +No specific display format is required by IEEE\ Std\ 1003.1-2001. +.LP +Explicit dependence on the ASCII character set has been avoided where +possible, hence the use of the phrase an +"implementation-defined multi-character sequence" for the display +of non-printable characters in preference to the historical +usage of, for instance, \fB"^I"\fP for the <tab>. Implementations +are encouraged to conform to historical practice in the +absence of any strong reason to diverge. +.LP +Historically, all \fIex\fP commands beginning with the letter \fB'p'\fP +could be entered using capitalized versions of the +commands; for example, \fBP[rint]\fP, \fBPre[serve]\fP, and \fBPu[t]\fP +were all valid command names. +IEEE\ Std\ 1003.1-2001 permits, but does not require, this historical +practice because capital forms of the commands are +used by some implementations for other purposes. +.SS Put +.LP +Historically, an \fIex\fP \fBput\fP command, executed from open or +visual mode, was the same as the open or visual mode +\fBP\fP command, if the buffer was named and was cut in character +mode, and the same as the \fBp\fP command if the buffer was +named and cut in line mode. If the unnamed buffer was the source of +the text, the entire line from which the text was taken was +usually \fBput\fP, and the buffer was handled as if in line mode, +but it was possible to get extremely anomalous behavior. In +addition, using the \fBQ\fP command to switch into \fIex\fP mode, +and then doing a \fBput\fP often resulted in errors as well, +such as appending text that was unrelated to the (supposed) contents +of the buffer. For consistency and simplicity of +specification, IEEE\ Std\ 1003.1-2001 does not permit these behaviors. +All \fIex\fP \fBput\fP commands are required to +operate in line mode, and the contents of the buffers are not altered +by changing the mode of the editor. +.SS Read +.LP +Historically, an \fIex\fP \fBread\fP command executed from open or +visual mode, executed in an empty file, left an empty line +as the first line of the file. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 does not permit this +behavior. Historically, a \fBread\fP in open or visual mode from a +program left the cursor at the last line read in, not the +first. For consistency, IEEE\ Std\ 1003.1-2001 does not permit this +behavior. +.LP +Historical implementations of \fIex\fP were unable to undo \fBread\fP +commands that read from the output of a program. For +consistency, IEEE\ Std\ 1003.1-2001 does not permit this behavior. +.LP +Historically, the \fIex\fP and \fIvi\fP message after a successful +\fBread\fP or +\fBwrite\fP command specified "characters", not "bytes". IEEE\ Std\ 1003.1-2001 +requires that the number of bytes be +displayed, not the number of characters, because it may be difficult +in multi-byte implementations to determine the number of +characters read. Implementations are encouraged to clarify the message +displayed to the user. +.LP +Historically, reads were not permitted on files other than type regular, +except that FIFO files could be read (probably only +because they did not exist when \fIex\fP and \fIvi\fP were originally +written). Because the +historical \fIex\fP evaluated \fBread!\fP and \fBread\ !\fP equivalently, +there can be no optional way to force the read. +IEEE\ Std\ 1003.1-2001 permits, but does not require, this behavior. +.SS Recover +.LP +Some historical implementations of the editor permitted users to recover +the edit buffer contents from a previous edit session, +and then exit without saving those contents (or explicitly discarding +them). The intent of IEEE\ Std\ 1003.1-2001 in +requiring that the edit buffer be treated as already modified is to +prevent this user error. +.SS Rewind +.LP +Historical implementations supported the \fBrewind\fP command when +the user was editing the first file in the list; that is, +the file that the \fBrewind\fP command would edit. IEEE\ Std\ 1003.1-2001 +requires conformance to historical practice. +.SS Substitute +.LP +Historically, \fIex\fP accepted an \fBr\fP option to the \fBs\fP command. +The effect of the \fBr\fP option was to use the +last regular expression used in any command as the pattern, the same +as the \fB~\fP command. The \fBr\fP option is not +required by IEEE\ Std\ 1003.1-2001. Historically, the \fBc\fP and +\fBg\fP options were toggled; for example, the command +\fB:s/abc/def/\fP was the same as \fBs/abc/def/ccccgggg\fP. For simplicity +of specification, IEEE\ Std\ 1003.1-2001 does +not permit this behavior. +.LP +The tilde command is often used to replace the last search RE. For +example, in the sequence: +.sp +.RS +.nf + +\fBs/red/blue/ +/green +~ +\fP +.fi +.RE +.LP +the \fB~\fP command is equivalent to: +.sp +.RS +.nf + +\fBs/green/blue/ +\fP +.fi +.RE +.LP +Historically, \fIex\fP accepted all of the following forms: +.sp +.RS +.nf + +\fBs/abc/def/ +s/abc/def +s/abc/ +s/abc +\fP +.fi +.RE +.LP +IEEE\ Std\ 1003.1-2001 requires conformance to this historical practice. +.LP +The \fBs\fP command presumes that the \fB'^'\fP character only occupies +a single column in the display. Much of the +\fIex\fP and \fIvi\fP specification presumes that the <space> only +occupies a single +column in the display. There are no known character sets for which +this is not true. +.LP +Historically, the final column position for the substitute commands +was based on previous column movements; a search for a +pattern followed by a substitution would leave the column position +unchanged, while a 0 command followed by a substitution would +change the column position to the first non- <blank>. For consistency +and simplicity of specification, +IEEE\ Std\ 1003.1-2001 requires that the final column position always +be set to the first non- <blank>. +.SS Set +.LP +Historical implementations redisplayed all of the options for each +occurrence of the \fBall\fP keyword. +IEEE\ Std\ 1003.1-2001 permits, but does not require, this behavior. +.SS Tag +.LP +No requirement is made as to where \fIex\fP and \fIvi\fP shall look +for the file referenced +by the tag entry. Historical practice has been to look for the path +found in the \fBtags\fP file, based on the current directory. +A useful extension found in some implementations is to look based +on the directory containing the tags file that held the entry, as +well. No requirement is made as to which reference for the tag in +the tags file is used. This is deliberate, in order to permit +extensions such as multiple entries in a tags file for a tag. +.LP +Because users often specify many different tags files, some of which +need not be relevant or exist at any particular time, +IEEE\ Std\ 1003.1-2001 requires that error messages about problem +tags files be displayed only if the requested tag is not +found, and then, only once for each time that the \fBtag\fP edit option +is changed. +.LP +The requirement that the current edit buffer be unmodified is only +necessary if the file indicated by the tag entry is not the +same as the current file (as defined by the current pathname). Historically, +the file would be reloaded if the filename had +changed, as well as if the filename was different from the current +pathname. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 does not permit this behavior, requiring that +the name be the only factor in the decision. +.LP +Historically, \fIvi\fP only searched for tags in the current file +from the current cursor to +the end of the file, and therefore, if the \fBwrapscan\fP option was +not set, tags occurring before the current cursor were not +found. IEEE\ Std\ 1003.1-2001 considers this a bug, and implementations +are required to search for the first occurrence in +the file, regardless. +.SS Undo +.LP +The \fBundo\fP description deliberately uses the word "modified". +The \fBundo\fP command is not intended to undo commands +that replace the contents of the edit buffer, such as \fBedit\fP, +\fBnext\fP, \fBtag\fP, or \fBrecover\fP. +.LP +Cursor positioning after the \fBundo\fP command was inconsistent in +the historical \fIvi\fP, sometimes attempting to restore the original +cursor position ( \fBglobal\fP, \fBundo\fP, +and \fBv\fP commands), and sometimes, in the presence of maps, placing +the cursor on the last line added or changed instead of the +first. IEEE\ Std\ 1003.1-2001 requires a simplified behavior for consistency +and simplicity of specification. +.SS Version +.LP +The \fBversion\fP command cannot be exactly specified since there +is no widely-accepted definition of what the version +information should contain. Implementations are encouraged to do something +reasonably intelligent. +.SS Write +.LP +Historically, the \fIex\fP and \fIvi\fP message after a successful +\fBread\fP or +\fBwrite\fP command specified "characters", not "bytes". IEEE\ Std\ 1003.1-2001 +requires that the number of bytes be +displayed, not the number of characters because it may be difficult +in multi-byte implementations to determine the number of +characters written. Implementations are encouraged to clarify the +message displayed to the user. +.LP +Implementation-defined tests are permitted so that implementations +can make additional checks; for example, for locks or file +modification times. +.LP +Historically, attempting to append to a nonexistent file caused an +error. It has been left unspecified in +IEEE\ Std\ 1003.1-2001 to permit implementations to let the \fBwrite\fP +succeed, so that the append semantics are similar +to those of the historical \fIcsh\fP. +.LP +Historical \fIvi\fP permitted empty edit buffers to be written. However, +since the way \fIvi\fP got around dealing with "empty" files was to +always have a line in the edit buffer, no +matter what, it wrote them as files of a single, empty line. IEEE\ Std\ 1003.1-2001 +does not permit this behavior. +.LP +Historically, \fIex\fP restored standard output and standard error +to their values as of when \fIex\fP was invoked, before +writes to programs were performed. This could disturb the terminal +configuration as well as be a security issue for some terminals. +IEEE\ Std\ 1003.1-2001 does not permit this, requiring that the program +output be captured and displayed as if by the +\fIex\fP \fBprint\fP command. +.SS Adjust Window +.LP +Historically, the line count was set to the value of the \fBscroll\fP +option if the type character was end-of-file. This +feature was broken on most historical implementations long ago, however, +and is not documented anywhere. For this reason, +IEEE\ Std\ 1003.1-2001 is resolutely silent. +.LP +Historically, the \fBz\fP command was <blank>-sensitive and \fBz\ +\fP +and \fBz\ -\fP did different things than +\fBz+\fP and \fBz-\fP because the type could not be distinguished +from a flag. (The commands \fBz\\fP. and \fBz\ =\fP +were historically invalid.) IEEE\ Std\ 1003.1-2001 requires conformance +to this historical practice. +.LP +Historically, the \fBz\fP command was further <blank>-sensitive in +that the \fIcount\fP could not be +<blank>-delimited; for example, the commands \fBz=\ 5\fP and \fBz-\ 5\fP +were also invalid. Because the +\fIcount\fP is not ambiguous with respect to either the type character +or the flags, this is not permitted by +IEEE\ Std\ 1003.1-2001. +.SS Escape +.LP +Historically, \fIex\fP filter commands only read the standard output +of the commands, letting standard error appear on the +terminal as usual. The \fIvi\fP utility, however, read both standard +output and standard error. +IEEE\ Std\ 1003.1-2001 requires the latter behavior for both \fIex\fP +and \fIvi\fP, +for consistency. +.SS Shift Left and Shift Right +.LP +Historically, it was possible to add shift characters to increase +the effect of the command; for example, \fB<<<\fP +outdented (or \fB>>>\fP indented) the lines 3 levels of indentation +instead of the default 1. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice. +.SS <control>-D +.LP +Historically, the <control>-D command erased the prompt, providing +the user with an unbroken presentation of lines from +the edit buffer. This is not required by IEEE\ Std\ 1003.1-2001; implementations +are encouraged to provide it if possible. +Historically, the <control>-D command took, and then ignored, a \fIcount\fP. +IEEE\ Std\ 1003.1-2001 does not permit +this behavior. +.SS Write Line Number +.LP +Historically, the \fIex\fP \fB=\fP command, when executed in \fIex\fP +mode in an empty edit buffer, reported 0, and from open +or visual mode, reported 1. For consistency and simplicity of specification, +IEEE\ Std\ 1003.1-2001 does not permit this +behavior. +.SS Execute +.LP +Historically, \fIex\fP did not correctly handle the inclusion of text +input commands (that is, \fBappend\fP, \fBinsert\fP, +and \fBchange\fP) in executed buffers. IEEE\ Std\ 1003.1-2001 does +not permit this exclusion for consistency. +.LP +Historically, the logical contents of the buffer being executed did +not change if the buffer itself were modified by the +commands being executed; that is, buffer execution did not support +self-modifying code. IEEE\ Std\ 1003.1-2001 requires +conformance to historical practice. +.LP +Historically, the \fB@\fP command took a range of lines, and the \fB@\fP +buffer was executed once per line, with the current +line ( \fB'.'\fP ) set to each specified line. IEEE\ Std\ 1003.1-2001 +requires conformance to historical practice. +.LP +Some historical implementations did not notice if errors occurred +during buffer execution. This, coupled with the ability to +specify a range of lines for the \fIex\fP \fB@\fP command, makes it +trivial to cause them to drop \fBcore\fP. +IEEE\ Std\ 1003.1-2001 requires that implementations stop buffer execution +if any error occurs, if the specified line +doesn't exist, or if the contents of the edit buffer itself are replaced +(for example, the buffer executes the \fIex\fP +\fB:edit\fP command). +.SS Regular Expressions in ex +.LP +Historical practice is that the characters in the replacement part +of the last \fBs\fP command-that is, those matched by +entering a \fB'~'\fP in the regular expression-were not further expanded +by the regular expression engine. So, if the +characters contained the string \fB"a.,"\fP they would match \fB'a'\fP +followed by \fB".,"\fP and not \fB'a'\fP +followed by any character. IEEE\ Std\ 1003.1-2001 requires conformance +to historical practice. +.SS Edit Options in ex +.LP +The following paragraphs describe the historical behavior of some +edit options that were not, for whatever reason, included in +IEEE\ Std\ 1003.1-2001. Implementations are strongly encouraged to +only use these names if the functionality described here +is fully supported. +.TP 7 +\fBextended\fP +The \fBextended\fP edit option has been used in some implementations +of \fIvi\fP to +provide extended regular expressions instead of basic regular expressions +This option was omitted from +IEEE\ Std\ 1003.1-2001 because it is not widespread historical practice. +.TP 7 +\fBflash\fP +The \fBflash\fP edit option historically caused the screen to flash +instead of beeping on error. This option was omitted from +IEEE\ Std\ 1003.1-2001 because it is not found in some historical +implementations. +.TP 7 +\fBhardtabs\fP +The \fBhardtabs\fP edit option historically defined the number of +columns between hardware tab settings. This option was +omitted from IEEE\ Std\ 1003.1-2001 because it was believed to no +longer be generally useful. +.TP 7 +\fBmodeline\fP +The \fBmodeline\fP (sometimes named \fBmodelines\fP) edit option historically +caused \fIex\fP or \fIvi\fP to read the five first and last lines +of the file for editor commands. This option is a +security problem, and vendors are strongly encouraged to delete it +from historical implementations. +.TP 7 +\fBopen\fP +The \fBopen\fP edit option historically disallowed the \fIex\fP \fBopen\fP +and \fBvisual\fP commands. This edit option was +omitted because these commands are required by IEEE\ Std\ 1003.1-2001. +.TP 7 +\fBoptimize\fP +The \fBoptimize\fP edit option historically expedited text throughput +by setting the terminal to not do automatic +<carriage-return>s when printing more than one logical line of output. +This option was omitted from +IEEE\ Std\ 1003.1-2001 because it was intended for terminals without +addressable cursors, which are rarely, if ever, still +used. +.TP 7 +\fBruler\fP +The \fBruler\fP edit option has been used in some implementations +of \fIvi\fP to present a +current row/column ruler for the user. This option was omitted from +IEEE\ Std\ 1003.1-2001 because it is not widespread +historical practice. +.TP 7 +\fBsourceany\fP +The \fBsourceany\fP edit option historically caused \fIex\fP or \fIvi\fP +to source +start-up files that were owned by users other than the user running +the editor. This option is a security problem, and vendors are +strongly encouraged to remove it from their implementations. +.TP 7 +\fBtimeout\fP +The \fBtimeout\fP edit option historically enabled the (now standard) +feature of only waiting for a short period before +returning keys that could be part of a macro. This feature was omitted +from IEEE\ Std\ 1003.1-2001 because its behavior is +now standard, it is not widely useful, and it was rarely documented. +.TP 7 +\fBverbose\fP +The \fBverbose\fP edit option has been used in some implementations +of \fIvi\fP to cause +\fIvi\fP to output error messages for common errors; for example, +attempting to move the cursor +past the beginning or end of the line instead of only alerting the +screen. (The historical \fIvi\fP only alerted the terminal and presented +no message for such errors. The historical editor +option \fBterse\fP did not select when to present error messages, +it only made existing error messages more or less verbose.) This +option was omitted from IEEE\ Std\ 1003.1-2001 because it is not widespread +historical practice; however, implementors are +encouraged to use it if they wish to provide error messages for naive +users. +.TP 7 +\fBwraplen\fP +The \fBwraplen\fP edit option has been used in some implementations +of \fIvi\fP to specify +an automatic margin measured from the left margin instead of from +the right margin. This is useful when multiple screen sizes are +being used to edit a single file. This option was omitted from IEEE\ Std\ 1003.1-2001 +because it is not widespread +historical practice; however, implementors are encouraged to use it +if they add this functionality. +.sp +.SS autoindent, ai +.LP +Historically, the command \fB0a\fP did not do any autoindentation, +regardless of the current indentation of line 1. +IEEE\ Std\ 1003.1-2001 requires that any indentation present in line +1 be used. +.SS autoprint, ap +.LP +Historically, the \fBautoprint\fP edit option was not completely consistent +or based solely on modifications to the edit +buffer. Exceptions were the \fBread\fP command (when reading from +a file, but not from a filter), the \fBappend\fP, +\fBchange\fP, \fBinsert\fP, \fBglobal\fP, and \fBv\fP commands, all +of which were not affected by \fBautoprint\fP, and the +\fBtag\fP command, which was affected by \fBautoprint\fP. IEEE\ Std\ 1003.1-2001 +requires conformance to historical +practice. +.LP +Historically, the \fBautoprint\fP option only applied to the last +of multiple commands entered using vertical-bar delimiters; +for example, \fBdelete\fP <newline> was affected by \fBautoprint\fP, +but \fBdelete|version\fP <newline> was not. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice. +.SS autowrite, aw +.LP +Appending the \fB'!'\fP character to the \fIex\fP \fBnext\fP command +to avoid performing an automatic write was not +supported in historical implementations. IEEE\ Std\ 1003.1-2001 requires +that the behavior match the other \fIex\fP +commands for consistency. +.SS ignorecase, ic +.LP +Historical implementations of case-insensitive matching (the \fBignorecase\fP +edit option) lead to counterintuitive situations +when uppercase characters were used in range expressions. Historically, +the process was as follows: +.IP " 1." 4 +Take a line of text from the edit buffer. +.LP +.IP " 2." 4 +Convert uppercase to lowercase in text line. +.LP +.IP " 3." 4 +Convert uppercase to lowercase in regular expressions, except in character +class specifications. +.LP +.IP " 4." 4 +Match regular expressions against text. +.LP +.LP +This would mean that, with \fBignorecase\fP in effect, the text: +.sp +.RS +.nf + +\fBThe cat sat on the mat +\fP +.fi +.RE +.LP +would be matched by +.sp +.RS +.nf + +\fB/^the/ +\fP +.fi +.RE +.LP +but not by: +.sp +.RS +.nf + +\fB/^[A-Z]he/ +\fP +.fi +.RE +.LP +For consistency with other commands implementing regular expressions, +IEEE\ Std\ 1003.1-2001 does not permit this +behavior. +.SS paragraphs, para +.LP +The ISO\ POSIX-2:1993 standard made the default \fBparagraphs\fP and +\fBsections\fP edit options implementation-defined, +arguing they were historically oriented to the UNIX system \fItroff\fP +text formatter, and a "portable user" could use the +\fB{\fP, \fB}\fP, \fB[[\fP, \fB]]\fP, \fB(\fP, and \fB)\fP commands +in open or visual mode and have the cursor stop in +unexpected places. IEEE\ Std\ 1003.1-2001 specifies their values in +the POSIX locale because the unusual grouping (they +only work when grouped into two characters at a time) means that they +cannot be used for general-purpose movement, regardless. +.SS readonly +.LP +Implementations are encouraged to provide the best possible information +to the user as to the read-only status of the file, with +the exception that they should not consider the current special privileges +of the process. This provides users with a safety net +because they must force the overwrite of read-only files, even when +running with additional privileges. +.LP +The \fBreadonly\fP edit option specification largely conforms to historical +practice. The only difference is that historical +implementations did not notice that the user had set the \fBreadonly\fP +edit option in cases where the file was already marked +read-only for some reason, and would therefore reinitialize the \fBreadonly\fP +edit option the next time the contents of the edit +buffer were replaced. This behavior is disallowed by IEEE\ Std\ 1003.1-2001. +.SS report +.LP +The requirement that lines copied to a buffer interact differently +than deleted lines is historical practice. For example, if +the \fBreport\fP edit option is set to 3, deleting 3 lines will cause +a report to be written, but 4 lines must be copied before a +report is written. +.LP +The requirement that the \fIex\fP \fBglobal\fP, \fBv\fP, \fBopen\fP, +\fBundo\fP, and \fBvisual\fP commands present reports +based on the total number of lines added or deleted during the command +execution, and that commands executed by the \fBglobal\fP +and \fBv\fP commands not present reports, is historical practice. +IEEE\ Std\ 1003.1-2001 extends historical practice by +requiring that buffer execution be treated similarly. The reasons +for this are two-fold. Historically, only the report by the last +command executed from the buffer would be seen by the user, as each +new report would overwrite the last. In addition, the standard +developers believed that buffer execution had more in common with +\fBglobal\fP and \fBv\fP commands than it did with other +\fIex\fP commands, and should behave similarly, for consistency and +simplicity of specification. +.SS showmatch, sm +.LP +The length of time the cursor spends on the matching character is +unspecified because the timing capabilities of systems are +often inexact and variable. The time should be long enough for the +user to notice, but not long enough for the user to become +annoyed. Some implementations of \fIvi\fP have added a \fBmatchtime\fP +option that permits +users to set the number of 0,1 second intervals the cursor pauses +on the matching character. +.SS showmode +.LP +The \fBshowmode\fP option has been used in some historical implementations +of \fIex\fP and \fIvi\fP to display the current editing mode when +in open or visual mode. The editing modes have +generally included "command" and "input", and sometimes other modes +such as "replace" and "change". The string was usually +displayed on the bottom line of the screen at the far right-hand corner. +In addition, a preceding \fB'*'\fP character often +denoted whether the contents of the edit buffer had been modified. +The latter display has sometimes been part of the +\fBshowmode\fP option, and sometimes based on another option. This +option was not available in the 4 BSD historical implementation +of \fIvi\fP, but was viewed as generally useful, particularly to novice +users, and is required +by IEEE\ Std\ 1003.1-2001. +.LP +The \fBsmd\fP shorthand for the \fBshowmode\fP option was not present +in all historical implementations of the editor. +IEEE\ Std\ 1003.1-2001 requires it, for consistency. +.LP +Not all historical implementations of the editor displayed a mode +string for command mode, differentiating command mode from +text input mode by the absence of a mode string. IEEE\ Std\ 1003.1-2001 +permits this behavior for consistency with +historical practice, but implementations are encouraged to provide +a display string for both modes. +.SS slowopen +.LP +Historically the \fBslowopen\fP option was automatically set if the +terminal baud rate was less than 1200 baud, or if the baud +rate was 1200 baud and the \fBredraw\fP option was not set. The \fBslowopen\fP +option had two effects. First, when inserting +characters in the middle of a line, characters after the cursor would +not be pushed ahead, but would appear to be overwritten. +Second, when creating a new line of text, lines after the current +line would not be scrolled down, but would appear to be +overwritten. In both cases, ending text input mode would cause the +screen to be refreshed to match the actual contents of the edit +buffer. Finally, terminals that were sufficiently intelligent caused +the editor to ignore the \fBslowopen\fP option. +IEEE\ Std\ 1003.1-2001 permits most historical behavior, extending +historical practice to require \fBslowopen\fP behaviors +if the edit option is set by the user. +.SS tags +.LP +The default path for tags files is left unspecified as implementations +may have their own \fBtags\fP implementations that do +not correspond to the historical ones. The default \fBtags\fP option +value should probably at least include the file +\fB\&./tags\fP. +.SS term +.LP +Historical implementations of \fIex\fP and \fIvi\fP ignored changes +to the \fBterm\fP edit +option after the initial terminal information was loaded. This is +permitted by IEEE\ Std\ 1003.1-2001; however, +implementations are encouraged to permit the user to modify their +terminal type at any time. +.SS terse +.LP +Historically, the \fBterse\fP edit option optionally provided a shorter, +less descriptive error message, for some error +messages. This is permitted, but not required, by IEEE\ Std\ 1003.1-2001. +Historically, most common visual mode errors (for +example, trying to move the cursor past the end of a line) did not +result in an error message, but simply alerted the terminal. +Implementations wishing to provide messages for novice users are urged +to do so based on the \fBedit\fP option \fBverbose\fP, and +not \fBterse\fP. +.SS window +.LP +In historical implementations, the default for the \fBwindow\fP edit +option was based on the baud rate as follows: +.IP " 1." 4 +If the baud rate was less than 1200, the \fBedit\fP option \fBw300\fP +set the window value; for example, the line: +.sp +.RS +.nf + +\fBset w300=12 +\fP +.fi +.RE +.LP +would set the window option to 12 if the baud rate was less than 1200. +.LP +.IP " 2." 4 +If the baud rate was equal to 1200, the \fBedit\fP option \fBw1200\fP +set the window value. +.LP +.IP " 3." 4 +If the baud rate was greater than 1200, the \fBedit\fP option \fBw9600\fP +set the window value. +.LP +.LP +The \fBw300\fP, \fBw1200\fP, and \fBw9600\fP options do not appear +in IEEE\ Std\ 1003.1-2001 because of their +dependence on specific baud rates. +.LP +In historical implementations, the size of the window displayed by +various commands was related to, but not necessarily the same +as, the \fBwindow\fP edit option. For example, the size of the window +was set by the \fIex\fP command \fBvisual 10\fP, but it +did not change the value of the \fBwindow\fP edit option. However, +changing the value of the \fBwindow\fP edit option did change +the number of lines that were displayed when the screen was repainted. +IEEE\ Std\ 1003.1-2001 does not permit this behavior +in the interests of consistency and simplicity of specification, and +requires that all commands that change the number of lines +that are displayed do it by setting the value of the \fBwindow\fP +edit option. +.SS wrapmargin, wm +.LP +Historically, the \fBwrapmargin\fP option did not affect maps inserting +characters that also had associated \fIcount\fPs; for +example \fB:map\ K\ 5aABC\ DEF\fP. Unfortunately, there are widely +used maps that depend on this behavior. For +consistency and simplicity of specification, IEEE\ Std\ 1003.1-2001 +does not permit this behavior. +.LP +Historically, \fBwrapmargin\fP was calculated using the column display +width of all characters on the screen. For example, an +implementation using \fB"^I"\fP to represent <tab>s when the \fBlist\fP +edit option was set, where \fB'^'\fP and +\fB'I'\fP each took up a single column on the screen, would calculate +the \fBwrapmargin\fP based on a value of 2 for each +<tab>. The \fBnumber\fP edit option similarly changed the effective +length of the line as well. +IEEE\ Std\ 1003.1-2001 requires conformance to historical practice. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fICommand Search and Execution\fP, \fIctags\fP, \fIed\fP, \fIsed\fP, +\fIsh\fP, \fIstty\fP, \fIvi\fP, the System Interfaces volume +of IEEE\ Std\ 1003.1-2001, \fIaccess\fP() +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . |