Fix Watch Command Not Showing Colors for ‘git status’

I encountered the 'color-stealing' issues with watch, it's because watch uses a simple /bin/sh output style, which clobbers any color, aliases, shortcuts... the whole shebang!

So I cobbled this together, placed in my .bashrc, allows me to use all my own aliases, shortcuts and whatnot:

Usage:
    watcher 20 'somecommand | apipe | grep'

The number is the delay between updates, in seconds, the command can include anything you can quote.

###### 'watch' workalike, lets me use my aliases and such
function watcher() { WATCHERTIME=$1 ; WATCHERFILE=/tmp/watcher$$ ; shift ; while true ; do WATCHERHEIGHT=$(($LINES - 5)) ; ( eval $* ) | tail -n ${WATCHERHEIGHT} > ${WATCHERFILE} 2>/dev/null; clear ; /bin/echo -n "Every ${WATCHERTIME} seconds - " ; date ; /bin/echo ; cat ${WATCHERFILE} ; \rm -f ${WATCHERFILE} ; /bin/echo ; /bin/echo "==" ; sleep ${WATCHERTIME} ; done ; }

To break it down:

function watcher()
{ 
  WATCHERTIME=$1
  WATCHERFILE=/tmp/watcher$$
  shift
  while true; do
    WATCHERHEIGHT=$(($LINES - 5))
    ( eval $* ) | tail -n ${WATCHERHEIGHT} > ${WATCHERFILE} 2>/dev/null
    clear
    /bin/echo -n "Every ${WATCHERTIME} seconds - "
    date
    /bin/echo
    cat ${WATCHERFILE}
    \rm -f ${WATCHERFILE}
    /bin/echo
    /bin/echo "=="
    sleep ${WATCHERTIME}
  done
}

It determines the current screen height in lines, subtracts out enough for its own output, then repeatedly executes the command given, then clears the screen, displays the output and waits for the next loop. It displays a short '==' at the bottom to signify that's where the output ended. Sometime's it's helpful to know this.

I did it this way so there was smallest possible delay when displaying. if you don't capture output and then display, you get a long pause, then the output... icky.

Since it doesn't clobber colors, you get everything you're used to getting. Enjoy!

It turns out that watch does work with color output. But specifically for grep you should make some workaround (according to grep --color adds ANSI code ESC[K - This can change displayed text)

watch --color "GREP_COLORS=ne grep --color=always .* *"