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CONSOLE(4)                    Linux User'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  com-
       piled  into  the  kernel (in tty.h: #define NR_CONSOLES 8) and could be
       changed by editing and recompiling.  Since version 1.1.54 virtual  con-
       soles 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  allo-
       cated  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.


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.  All  escape  sequences  can  be  found  in  con-
       sole_codes(4).


FILES
       /dev/console
       /dev/tty*


SEE ALSO
       charsets(4),   console_codes(4),  console_ioctl(4),  mknod(1),  tty(4),
       ttys(4),  getty(8),  init(8),  chvt(1),  open(1),  deallocvt(1),  load-
       keys(1), resizecons(8), consolechars(8), mapscrn(8).



Console tools                     28 Oct 1997                       CONSOLE(4)