git-in-repo

#!/usr/bin/env bash

app_name="$(basename "${BASH_SOURCE[0]}")"

print_help() {
	expand -t 4 << EOF
Usage:
	$app_name
		Returns 0 if current working directory is a Git repository, non-zero otherwise.

Options:
	-q, --quiet
		Suppress output.

	-s, --silent
		Silence git stderr.

	-?, --help
		Show this help information and exit.
EOF
}

quiet=0
silent=0

while [[ $# -gt 0 ]]; do
	case "$1" in
		-q|--quiet)
			quiet=1
			shift
			;;
		-s|--silent)
			silent=1
			shift
			;;
		-\?|--help)
			print_help
			exit 0
			;;
		-*)
			echo "$app_name: [Error] Unknown option: $1" >&2
			exit 1
			;;
		*)
			echo "$app_name: [Error] Unexpected argument: $1" >&2
			exit 1
			;;
	esac
done

if [[ silent -eq 0 ]]; then
	git rev-parse --git-dir > /dev/null
	success=$?
else
	git rev-parse --git-dir &> /dev/null
	success=$?
fi

if [[ quiet -eq 0 ]]; then
	if [[ success -eq 0 ]];then
		echo "yes"
	else
		echo "no"
	fi
fi

exit "$success"