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

NAME         top

       console - console terminal and virtual consoles

DESCRIPTION         top

       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(1) (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).

FILES         top


SEE ALSO         top

       chvt(1), deallocvt(1), init(1), loadkeys(1), mknod(1), openvt(1),
       console_codes(4), console_ioctl(4), tty(4), ttyS(4), charsets(7),
       agetty(8), mapscrn(8), mingetty(8), resizecons(8), setfont(8)

COLOPHON         top

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Linux                            1994-10-31                       CONSOLE(4)