console

CONSOLE(4)                 Linux Programmer's Manual                CONSOLE(4)



NAME
       console - console terminal and virtual consoles

DESCRIPTION
       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 getty(8) on the console; (b) ask open(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 disalloc(8) will free the memory taken by the screen
       buffers for consoles that no longer have any associated process.


PROPERTIES
       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.


FILES
       /dev/console
       /dev/tty*

SEE ALSO
       chvt(1), loadkeys(1), mknod (1), open(1), tty(4), ttys(4), disalloc(8),
       getty(8), init(8), resizecons(8), setfont(8), mapscrn(8).



Linux                          October 31, 1994                     CONSOLE(4)