NAME | DESCRIPTION | FILES | SEE ALSO | COLOPHON
CONSOLE(4) Linux Programmer's Manual CONSOLE(4)
console - console terminal and virtual consoles
A Linux system has up to 63 virtual consoles (character devices with major
number 4 and minor number 1 to 63), usually called /dev/ttyn with 1 <= n <=
63. The current console is also addressed by /dev/console or /dev/tty0, the
character device with major number 4 and minor number 0. The device files
/dev/* are usually created using the script MAKEDEV, or using mknod(1),
usually with mode 0622 and owner root.tty.
Before kernel version 1.1.54 the number of virtual consoles was compiled into
the kernel (in tty.h: #define NR_CONSOLES 8) and could be changed by editing
and recompiling. Since version 1.1.54 virtual consoles are created on the
fly, as soon as they are needed.
Common ways to start a process on a console are: (a) tell init(8) (in
inittab(5)) to start a mingetty(8) (or agetty(8)) on the console; (b) ask
openvt(1) to start a process on the console; (c) start X -- it will find the
first unused console, and display its output there. (There is also the
ancient doshell(8).)
Common ways to switch consoles are: (a) use Alt+Fn or Ctrl+Alt+Fn to switch to
console n; AltGr+Fn might bring you to console n+12 [here Alt and AltGr refer
to the left and right Alt keys, respectively]; (b) use Alt+RightArrow or
Alt+LeftArrow to cycle through the presently allocated consoles; (c) use the
program chvt(1). (The key mapping is user settable, see loadkeys(1); the
above mentioned key combinations are according to the default settings.)
The command deallocvt(1) (formerly disalloc) will free the memory taken by the
screen buffers for consoles that no longer have any associated process.
Consoles carry a lot of state. I hope to document that some other time. The
most important fact is that the consoles simulate vt100 terminals. In
particular, a console is reset to the initial state by printing the two
characters ESC c. All escape sequences can be found in console_codes(4).
/dev/console
/dev/tty*
chvt(1), deallocvt(1), loadkeys(1), mknod(1), openvt(1), console_codes(4),
console_ioctl(4), tty(4), ttyS(4), charsets(7), agetty(8), init(8),
mapscrn(8), mingetty(8), resizecons(8), setfont(8)
This page is part of release 3.23 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
Linux 1994-10-31 CONSOLE(4)