WATCH(1) Linux User's Manual WATCH(1)NAMEgnu-watch - execute a program periodically, showing output fullscreen
SYNOPSISgnu-watch [-dhvt] [-n <seconds>] [--differences[=cumulative]] [--help]
[--interval=<seconds>] [--no-title] [--version] <command>
DESCRIPTIONgnu-watch runs command repeatedly, displaying its output (the first
screenfull). This allows you to watch the program output change over
time. By default, the program is run every 2 seconds; use -n or
--interval to specify a different interval.
The -d or --differences flag will highlight the differences between
successive updates. The --cumulative option makes highlighting
"sticky", presenting a running display of all positions that have ever
changed. The -t or --no-title option turns off the header showing the
interval, command, and current time at the top of the display, as well
as the following blank line.
gnu-watch will run until interrupted.
NOTE
Note that command is given to "sh -c" which means that you may need to
use extra quoting to get the desired effect.
Note that POSIX option processing is used (i.e., option processing
stops at the first non-option argument). This means that flags after
command don't get interpreted by gnu-watch itself.
EXAMPLES
To watch for mail, you might do
gnu-watch-n 60 from
To watch the contents of a directory change, you could use
gnu-watch-d ls -l
If you're only interested in files owned by user joe, you might use
gnu-watch-d 'ls -l | fgrep joe'
To see the effects of quoting, try these out
gnu-watch echo $$
gnu-watch echo '$$'
gnu-watch echo "'"'$$'"'"
You can watch for your administrator to install the latest kernel with
gnu-watch uname -r
(Just kidding.)
BUGS
Upon terminal resize, the screen will not be correctly repainted until
the next scheduled update. All --differences highlighting is lost on
that update as well.
Non-printing characters are stripped from program output. Use "cat -v"
as part of the command pipeline if you want to see them.
AUTHORS
The original watch was written by Tony Rems <rembo@unisoft.com> in
1991, with mods and corrections by Francois Pinard. It was reworked
and new features added by Mike Coleman <mkc@acm.org> in 1999. In 2005
it was modified for FreeBSD by Emanuel Haupt <ehaupt@critical.ch>.
1999 Apr 3 WATCH(1)