jek

dir=$(pwd -P)
until [ $dir = '/' ]; do
    [[ -e "${dir}/.hg" ]] && vcs=hg && break
    [[ -e "${dir}/.git" ]] && vcs=git && break
    dir=$(dirname ${dir})
done

if [ -z $vcs ]; then
    echo "error: not in a git or hg repo" 1>&2 && exit 1
else