VCS

VCS

NAME DESCRIPTION EXAMPLES FILES AUTHOR HISTORY SEE ALSO

NAME

vcs, vcsa - virtual console memory

DESCRIPTION

/dev/vcs0 is a character device with major number 7 and minor number 0, usually of mode 0644 and owner root.tty. It refers to the memory of the currently displayed virtual console terminal.

/dev/vcs[1-63? are character devices for virtual console terminals, they have major number 7 and minor number 1 to 63, usually mode 0644 and owner root.tty. /dev/vcsa[0-63? are the same, but including attributes, and prefixed with four bytes giving the screen dimensions and cursor position: lines, columns, x, y. (x = y = 0 at the top left corner of the screen.)

These replace the screendump ioctls of console(4), so the system administrator can control access using file system permissions.

The devices for the first eight virtual consoles may be

created by

for x in 0 1 2 3 4 5 6 7 8; do

mknod -m 644 /dev/vcs$x c 7 $x; mknod -m 644 /dev/vcsa$x c 7 $[$x+128?; done chown root:tty /dev/vcs* No ioctl() requests are supported.

EXAMPLES

You may do a screendump on vt3 by switching to vt1 and typing cat /dev/vcs3 . Note that the output does not contain newline characters, so some processing may be required, like in fold -w 81 /dev/vcs3 | lpr or (horrors) setterm -dump 3 -file /proc/self/fd/1.

The /dev/vcsa0 device is used for Braille support.

This program displays the character and screen attributes under the cursor of the second virtual console, then changes

the background color there

1. include

FILES

/dev/vcs[0-63? /dev/vcsa[0-63?

AUTHOR

Andries Brouwer

HISTORY

Introduced with version 1.1.92 of the Linux kernel.

SEE ALSO

console(4), tty(4), ttys(4), selection(1)?