VCS Section: Linux Programmer's Manual (4) Updated: February 19, 2025 Index   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.) 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 >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. 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 <stdio.h> #include <fcntl.h> void main() { int fd; struct {char lines, cols, x, y;} scrn; char ch, attrib; fd = open("/dev/vcsa2", O_RDWR); (void)read(fd, &scrn, 4); (void)lseek(fd, 4 + 2*(scrn.y*scrn.cols + scrn.x), 0); (void)read(fd, &ch, 1); (void)read(fd, &attrib, 1); printf("ch='%c' attrib=0x%02x\n", ch, attrib); attrib ^= 0x10; (void)lseek(fd, -1, 1); (void)write(fd, &attrib, 1); }   FILES /dev/vcs[0-63] /dev/vcsa[0-63]   AUTHOR Andries Brouwer <aeb@cwi.nl>   HISTORY Introduced with version 1.1.92 of the Linux kernel.   SEE ALSO   Index NAME DESCRIPTION EXAMPLES FILES AUTHOR HISTORY SEE ALSO This document was created by using the manual pages. Time: 12:11:43 GMT, March 24, 2025