Git pre-commit hook to stop commit if changes contain sensitive values

pre-commit

#!/usr/bin/env bash

# pre-commit hook to prevent a commit if the commit includes changes that
# match a set of stop strings

FORBIDDEN='DO NOT COMMIT'

git diff --cached | grep -q -E "${FORBIDDEN}"
ret=$?
if [[ $ret = 0 ]]; then
  echo "COMMIT REJECTED\nFound changes containing forbidden \"${FORBIDDEN}\" references. Please remove them before committing"
  exit 1
fi