Backup utility

bak.sh

#!/bin/bash

backup() {
	mv "${1}" "${1}.bak"
}

restore() {
    mv "${1}" "${1/%\.bak/}"
}

handle() {
	EXT=${1##*.}
	case "${EXT}" in
	bak)
		restore "${1}"
		;;
	*)
		if [ -e "${1}.bak" ]; then
			restore "${1}.bak"
		else
			backup "${1}"
		fi
		;;
	esac
}

case "${1}" in
-a)
	for FILE in *.bak; do
		restore "${FILE}"
	done
	;;
*)
	for FILE in $*; do
		handle "${FILE}"
	done
	;;
esac