A bash git command that prints the shasum of your last commit. Just make it executable and put it in your PATH, then `git sha`.

git-sha

#!/usr/bin/env bash

##
# Use color by default if stdout is a terminal.
if [[ -t 1 ]]; then
	color=1
else
	color=0
fi

while (( $# )); do
	case "$1" in
		# Git redirects --help to the manpage.
		-h)
			printf "usage: git sum [-h --help] [--no-color]\n"
			exit
			;;
		--no-color)
			color=0
			shift 1
			;;
		*)
			printf "fatal: unrecognized option: %s\n" "$1" >&2
			exit 1
			;;
	esac
done

checksum=$(git rev-parse HEAD) || exit

if (( color )); then
	short_size=$(git config --get core.abbrev || printf "9")

	printf "%s\n" "$(tput bold)$(tput setaf 2)${checksum:0:short_size}$(tput setaf 5)${checksum:short_size}"
else
	printf "%s\n" "$checksum"
fi