VCSTIME(1) Linux User's Manual VCSTIME(1)NAME
vcstime - Show time in upper right hand corner of the console screen
SYNOPSIS
vcstime
DESCRIPTION
vcstime shows the current time in the upper right-hand corner of the console screen.
This simple program shows the current time in the corner of the console screen.
It needs to be run by root, in order to have write permissions to /dev/vcsa
AUTHORS
vcstime was written by Andries Brouwer, based on a suggestion by Miguel de Icaza. This manual page was Written by Alastair McKinstry,
Debian, Jan 2003.
Console tools 22 Jan 2003 VCSTIME(1)
Check Out this Related Man Page
VCS(4) Linux Programmer's Manual VCS(4)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 >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 <stdio.h>
#include <fcntl.h>
int 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
", ch, attrib);
attrib ^= 0x10;
(void)lseek(fd, -1, 1);
(void)write(fd, &attrib, 1);
return 0;
}
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 console(4), tty(4), ttys(4), selection(1)Linux 1995-02-19 VCS(4)
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