Get the tag for a commit, or the branch@hash. Useful for showing a version.

git-version.sh

#!/usr/bin/env bash

# Set repo_dir to folder this script lives in.
repo_dir=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd -P)
if [[ $# -eq 1 && -n "$1" && -d "$1" ]]; then
    # Script was called with an argument that is a path to a directory.
    repo_dir="$1"
fi

# Get tags for HEAD.
tag=$( git -C "${repo_dir}" tag --no-color --contains )
if [[ -z "${tag}" ]]; then
    # No tag, get branch and short commit hash.
    branch=$( git -C "${repo_dir}" branch --no-color --show-current )
    hash=$( git -C "${repo_dir}" log --no-color --max-count=1 --pretty='format:%h' )
    tag="${branch}@${hash}"
fi

echo "${tag}"