NAME
    watch - execute a program periodically, showing output fullscreen

SYNOPSIS
    watch  [-dhv] [-n <seconds>] [--differences[=cumulative]] [--help]
    [--interval=<seconds>] [--version] <command>

DESCRIPTION
    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.

    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 watch itself.

EXAMPLES
    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.)

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.