man4/console.4

   1 .\" Copyright (c) 1994 Andries Brouwer (aeb@cwi.nl), Mon Oct 31 21:03:19 MET 1994
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  10 .\" Modified, Sun Feb 26 14:58:45 1995, faith@cs.unc.edu
  11 .\" "
  12 .TH CONSOLE 4 1994-10-31 "Linux" "Linux Programmer's Manual"
  13 .SH NAME
  14 console \- console terminal and virtual consoles
  15 .SH DESCRIPTION
  16 A Linux system has up to 63 \fIvirtual consoles\fP
  17 (character devices with major number 4 and minor number 1 to 63),
  18 usually called \fI/dev/tty\fP\fIn\fP with 1 \(<= \fIn\fP \(<= 63.
  19 The current console is also addressed by
  20 \fI/dev/console\fP or \fI/dev/tty0\fP, the character device with
  21 major number 4 and minor number 0.
  22 The device files /dev/* are usually created using the script MAKEDEV,
  23 or using
  24 .BR mknod (1),
  25 usually with mode 0622 and owner root.tty.
  26 .LP
  27 Before kernel version 1.1.54 the number of virtual consoles was
  28 compiled into the kernel (in tty.h: #define NR_CONSOLES 8)
  29 and could be changed by editing and recompiling.
  30 Since version 1.1.54 virtual consoles are created on the fly,
  31 as soon as they are needed.
  32 .LP
  33 Common ways to start a process on a console are:
  34 (a) tell
  35 .BR init (8)
  36 (in
  37 .BR inittab (5))
  38 to start a
  39 .BR mingetty (8)
  40 (or
  41 .BR agetty (8))
  42 on the console;
  43 (b) ask
  44 .BR openvt (1)
  45 to start a process on the console;
  46 (c) start X\(emit will find the first unused console,
  47 and display its output there.
  48 (There is also the ancient
  49 .BR doshell (8).)
  50 .LP
  51 Common ways to switch consoles are: (a) use Alt+F\fIn\fP or
  52 Ctrl+Alt+F\fIn\fP to switch to console \fIn\fP; AltGr+F\fIn\fP
  53 might bring you to console \fIn\fP+12 [here Alt and AltGr refer
  54 to the left and right Alt keys, respectively];
  55 (b) use Alt+RightArrow or Alt+LeftArrow to cycle through
  56 the presently allocated consoles; (c) use the program
  57 .BR chvt (1).
  58 (The key mapping is user settable, see
  59 .BR loadkeys (1);
  60 the above mentioned key combinations are according to the default settings.)
  61 .LP
  62 The command
  63 .BR deallocvt (1)
  64 (formerly \fBdisalloc\fP)
  65 will free the memory taken by the screen buffers for consoles
  66 that no longer have any associated process.
  67 .SS Properties
  68 Consoles carry a lot of state.
  69 I hope to document that some other time.
  70 The most important fact is that the consoles simulate vt100 terminals.
  71 In particular, a console is reset to the initial state by printing the two
  72 characters ESC c.
  73 All escape sequences can be found in
  74 .BR console_codes (4).
  75 .SH FILES
  76 .I /dev/console
  77 .br
  78 .I /dev/tty*
  79 .SH SEE ALSO
  80 .BR chvt (1),
  81 .BR deallocvt (1),
  82 .BR loadkeys (1),
  83 .BR mknod (1),
  84 .BR openvt (1),
  85 .BR console_codes (4),
  86 .BR console_ioctl (4),
  87 .BR tty (4),
  88 .BR ttyS (4),
  89 .BR charsets (7),
  90 .BR agetty (8),
  91 .BR init (8),
  92 .BR mapscrn (8),
  93 .BR mingetty (8),
  94 .BR resizecons (8),
  95 .BR setfont (8)