cmdwatch - execute a program periodically, showing output fullscreen
cmdwatch [-dhv] [-n <seconds>] [--differences[=cumulative]]
[--help] [--interval=<seconds>] [--version] <command>
cmdwatch 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 --differences=cumulative option makes
highlighting "sticky", presenting a running display of all
positions that have ever changed.
cmdwatch will run until interrupted.
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 cmdwatch itself.
To watch for mail, you might do
- cmdwatch -n 60 from
To watch the contents of a directory change, you could use
- cmdwatch -d ls -l
If you're only interested in files owned by user joe, you might
- cmdwatch -d 'ls -l | fgrep joe'
To see the effects of quoting, try these out
- cmdwatch echo $$
- cmdwatch echo '$$'
- cmdwatch echo "'"'$$'"'"
You can watch for your administrator to install the latest kernel
- cmdwatch uname -r
Upon terminal resize, the screen will not be correctly repainted until the next
scheduled update. All --differences highlighting is lost on that update
Non-printing characters are stripped from program output. Use
"cat -v" as part of the command pipeline if you want to see
The original watch was written by Tony Rems <firstname.lastname@example.org> in
1991, with mods and corrections by Francois Pinard. It was reworked and new
features added by Mike Coleman <email@example.com> in 1999. This man page
based on the watch man page of the Linux User's Manual.