WATCH linux command manual

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

       watch - execute a program periodically, showing output fullscreen

       watch  [-dhvt]  [-n  ]  [--differences[=cumulative]] [--help]
       [--interval=] [--no-title] [--version] 

       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.

       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)