Watch.sh - a generic watch-for-files-and-restart-a-command utility for linux.

watch.sh

#!/usr/bin/env bash

# if you have issues, try increasing /proc/sys/fs/inotify/max_user_watches

usage(){
  echo "$0 -i 'INCLUDE_FILES' [-e 'EXCLUDE_FILES'] -c 'COMMAND'"
  cat << EOF
  watch.sh - a generic watch-for-files-and-restart-a-command utility for linux.
  Author: Max Kaye
  License: Public Domain
EOF
  echo "  Included files should be a 'find' pattern; e.g. '*.js'"
  echo "  Excluded files should be regex (processed using grep); e.g. 'node_modules/.*'"
  echo ""
  echo "  Example: ./watch.sh -i '*.js' -e 'node_modules/.*' -c 'npm run app'"
  echo ""
  exit 1
}

while [ $# -gt 0 ]; do
  case $1 in
    -c) command="$2";    shift 2 ;;
    -i) include="$2";    shift 2 ;;
    -e) exclude="$2";    shift 2 ;;
    -*) echo -e "$0: Unrecognized option: $1" >&2; usage ;;
    *) echo -e "$0: Unexpected argument: $1" >&2; usage ;;
  esac
done

if [[ "$command" == "" ]] || [[ "$include" == "" ]]; then
  echo -e "$0: Must include both -c and -i to specify command to run and included files to watch\n" >&2
  usage
fi

kill_my_jobs() {
  #echo "jobs to kill: $(jobs -p)"
  PID="-${1:-$(jobs -p)}"
  kill -SIGINT $PID || echo "Unable to kill process: $PID" >&2
}

sigint_handler() {
  kill_my_jobs
  echo ""
  exit
}

trap sigint_handler SIGINT

while true; do
  files_to_watch=$(find . -iname "$include" | grep -i -v "$exclude")
  nlines=$(echo "$files_to_watch" | wc -l)
  echo "Watching $nlines files"
  echo "$0: running command '$command'"
  setsid $command &
  PID="$!"
  echo "PID: $PID"
  inotifywait -e modify -e move -e create -e delete -e attrib $files_to_watch
  kill_my_jobs $PID
  #sleep 1
  wait
done