Manual dla watch

WATCH(1) Linux User's Manual WATCH(1)

watch - execute a program periodically, showing output fullscreen

watch [-dhvt] [-n <seconds>] [--differences[=cumulative]] [--help]
[--interval=<seconds>] [--no-title] [--version] <command>

watch runs command repeatedly, displaying its output (the first screen-
full). 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.

watch 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 watch itself.

To watch for mail, you might do

watch -n 60 from

To watch the contents of a directory change, you could use

watch -d ls -l

If you're only interested in files owned by user joe, you might use

watch -d 'ls -l | fgrep joe'

To see the effects of quoting, try these out

watch echo $$

watch echo '$$'

watch echo "'"'$$'"'"

You can watch for your administrator to install the latest kernel with

watch uname -r

(Just kidding.)

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.

The original watch was written by Tony Rems <> in
1991, with mods and corrections by Francois Pinard. It was reworked
and new features added by Mike Coleman <> in 1999.

1999 Apr 3 WATCH(1)