git pre-commit hook to check ansible yaml files with ansible-lint

git-hook-ansible-lint.sh

#!/bin/bash

if git rev-parse --verify HEAD &> /dev/null ; then
  against=HEAD
else
  against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

files=$(
  git diff-index --cached --name-only $against |
    grep -E '\.ya?ml$'
)

if [[ -n $files ]] ; then
  if ! command -v ansible-lint &> /dev/null ; then
    echo -e "\e[1m\e[33m[warn]\e[0m \e[1mansible-lint\e[0m is not installed, skipping tests" >&2
    exit 0
  fi
fi

for file in $files ; do
  tmp_lintr=$(mktemp)
  git show ":$file" > "$tmp_lintr"
  ansible-lint "$tmp_lintr" || exit 1
  rm -f "$tmp_lintr"
done