pre-commit hook (add to .git/hooks/pre-commit) to refuse to commit debugger strings

pre-commit.sh

#!/bin/sh
# Refuse to commit files with the string ZZZ present
# I frequently use ZZZ to mark a spot where I'm working on an issue so I can come back to it
#

NOCOMMIT="ZZZ"

files=$(git diff-index --name-status --cached HEAD | grep -v ^D | cut -c3-)

if [ "$files" != "" ]
then
  for f in $files
  do
    if [[ "$f" =~ [.](py|md|applescript|json)$ ]]
    then
      if [ "$(grep $NOCOMMIT $f)" != '' ]
      then
        echo "NOCOMMIT message present in file $f, aborting!"
        echo "$(grep -n -C 3 $NOCOMMIT $f)"
        exit 1
      fi
    fi
  done
fi