定時間看結果 — Watch

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

NAME
       watch - execute a program periodically, showing output fullscreen

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

DESCRIPTION
       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 --cumu-
       lative  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
       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  in 1991, with mods and corrections
       by Francois Pinard.  It was reworked and new features added by Mike Coleman  in 1999.

以下是應用範例

watch --interval=5 du -h /mnt/hgfs/mail2000/splunk84.tar.gz