1 .TH WATCH 1 "1999 Apr 3" " " "Linux User's Manual"
3 watch \- execute a program periodically, showing output fullscreen
6 .I [\-dhvt] [\-n <seconds>] [\-\-differences[=cumulative]] [\-\-help] [\-\-interval=<seconds>] [\-\-no\-title] [\-\-version] <command>
11 repeatedly, displaying its output (the first screenfull). This allows you to
12 watch the program output change over time. By default, the program is run
17 to specify a different interval.
23 flag will highlight the differences between successive updates. The
25 option makes highlighting "sticky", presenting a running display of all
26 positions that have ever changed. The
30 option turns off the header showing the interval, command, and current
31 time at the top of the display, as well as the following blank line.
34 will run until interrupted.
39 which means that you may need to use extra quoting to get the desired effect.
41 Note that POSIX option processing is used (i.e., option processing stops at
42 the first non-option argument). This means that flags after
44 don't get interpreted by
49 To watch for mail, you might do
53 To watch the contents of a directory change, you could use
57 If you're only interested in files owned by user joe, you might use
59 watch \-d 'ls \-l | fgrep joe'
61 To see the effects of quoting, try these out
69 You can watch for your administrator to install the latest kernel with
75 Upon terminal resize, the screen will not be correctly repainted until the
76 next scheduled update. All
78 highlighting is lost on that update as well.
80 Non-printing characters are stripped from program output. Use "cat -v" as
81 part of the command pipeline if you want to see them.
85 was written by Tony Rems <rembo@unisoft.com> in 1991, with mods and
86 corrections by Francois Pinard. It was reworked and new features added by
87 Mike Coleman <mkc@acm.org> in 1999.