console

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  con-
       soles  was  compiled  into  the  kernel (in tty.h: #define
       NR_CONSOLES 8) and could be changed by editing and  recom-
       piling.  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 con-
       sole; (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 asso-
       ciated process.

PROPERTIES

       Consoles carry a lot of state. I  hope  to  document  that
       some other time.  The most important fact is that the con-
       soles simulate vt100 terminals.  In particular, a  console
       is  reset to the initial state by printing the two charac-
       ters ESC c.

FILES

       /dev/console
       /dev/tty*

SEE ALSO

       console_ioctl(4), chvt(1), loadkeys(1), mknod(1), open(1),
       tty(4),  ttys(4),  disalloc(8), getty(8), init(8), resize-
       cons(8), setfont(8), mapscrn(8)