A git pre-commit hook to stop you from committing scratch code.

pre-commit

#!/bin/sh
# A hook to abort a commit if your diff adds XXX or FIXME.

# Set this config variable if you want to allow it anyway.
allowfixmes=$(git config hooks.allowfixmes)
disallow_list="XXX FIXME"

if [ "$allowfixmes" != "true" ]
then
  for disallow in $disallow_list
  do
    if [ "$(git diff --cached | egrep "^\+.*${disallow}" > /dev/null; echo $?)" -eq "0" ] # egrep exits with 0 if it finds at least one match
    then
      echo "Error: Your diff will commit ${disallow}:"
      echo
      git diff --cached -S"${disallow}"
      echo
      echo "To commit anyway, use \`git config --bool hooks.allowfixmes true\`"
      echo "to set the config variable that skips this check."
      exit 1
    fi
  done
fi

# Nothing disallowed added. Allow commit.
exit 0

And now changed color configuration in .gitconfig from "always" to "auto" and it works even without --color=never in pre-commit hook.