Pre commit git-hook that checks if there are changes that must not be committed. The changes should be marked with a NOCOMMIT flag.

pre-commit.sh

#!/bin/sh
#
# Do not commit files with the flag: NOCOMMIT

if git rev-parse --verify HEAD >/dev/null 2>&1
then
  against=HEAD
else
  # Initial commit: diff against an empty tree object
  against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

if test "$(git diff --cached $against | grep 'NOCOMMIT')"
then
  echo "ERROR: Attempt to commit not desired changes"
  echo
  echo "The changes are marked as NOCOMMIT. Use this flag to check"
  echo "when a change should not be committed"
  echo
  exit 1
fi

# exec git diff-index --check --cached $against --