deallocvt(1) [linux man page]

DEALLOCVT(1)						      General Commands Manual						      DEALLOCVT(1)

NAME

       deallocvt - deallocate unused virtual consoles

SYNOPSIS

       deallocvt [N ...]

DESCRIPTION

       The  command  deallocvt deallocates kernel memory and data structures for all unused virtual consoles.  If one or more arguments N ...  are
       given, only the corresponding consoles /dev/ttyN are deallocated.

       A virtual console is unused if it is not the foreground console, and no process has it open for reading or writing, and no  text  has  been
       selected on its screen.

SEE ALSO

       chvt(1), openvt(1)

								    17 Mar 1997 						      DEALLOCVT(1)

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 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  associ-
       ated 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 ter-
       minals.	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

       /dev/console
       /dev/tty*

SEE ALSO

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

COLOPHON

       This page is part of release 3.25 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    1994-10-31								CONSOLE(4)