vcs, vcsa — virtual console memory


/dev/vcs0 is a character device with major number 7 and minor number 0, usually with mode 0644 and ownership 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 ownership root:tty. /dev/vcsa[0−63] are the same, but using unsigned shorts (in host byte order) that include 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.)

When a 512-character font is loaded, the 9th bit position can be fetched by applying the ioctl(2) VT_GETHIFONTMASK operation (available in Linux kernels 2.6.18 and above) on /dev/tty[1−63]; the value is returned in the unsigned short pointed to by the third ioctl(2) argument.

These devices replace the screendump ioctl(2) operations of ioctl_console(2), so the system administrator can control access using filesystem 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];
chown root:tty /dev/vcs*

No ioctl(2) requests are supported.





Introduced with version 1.1.92 of the Linux kernel.


You may do a screendump on vt3 by switching to vt1 and typing

cat /dev/vcs3 >foo

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:

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/vt.h>

    int fd;
    char *device = "/dev/vcsa2";
    char *console = "/dev/tty2";
    struct {unsigned char lines, cols, x, y;} scrn;
    unsigned short s;
    unsigned short mask;
    unsigned char attrib;
    int ch;

    fd = open(console, O_RDWR);
    if (fd < 0) {
    if (ioctl(fd, VT_GETHIFONTMASK, &mask) < 0) {
    (void) close(fd);
    fd = open(device, O_RDWR);
    if (fd < 0) {
    (void) read(fd, &scrn, 4);
    (void) lseek(fd, 4 + 2*(scrn.y*scrn.cols + scrn.x), SEEK_SET);
    (void) read(fd, &s, 2);
    ch = s & 0xff;
    if (s & mask)
        ch |= 0x100;
    attrib = ((s & ~mask) >> 8);
    printf("ch=0x%03x attrib=0x%02x\n", ch, attrib);
    s ^= 0x1000;
    (void) lseek(fd, −2, SEEK_CUR);
    (void) write(fd, &s, 2);


ioctl_console(2), tty(4), ttyS(4), gpm(8)


This page is part of release 5.04 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at−pages/.

  Copyright (c) 1995 James R. Van Zandt <>
Sat Feb 18 09:11:07 EST 1995

This is free documentation; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
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Modified, Sun Feb 26 15:08:05 1995,
2007-12-17, Samuel Thibault <>:
    document the VT_GETHIFONTMASK ioctl