retry.sh: Retry a command until it succeeds

retry.sh

#!/bin/bash

# defaults
timeout=2s

function usage() {
	echo "USAGE: $0 [-i interval] <command>"
	echo "	Retry running <command> every <interval> until it succeeds"
}

# parse command line
while true; do
	case $1 in
	-h|--help)
		usage
		exit 0
		;;
	-i|--interval)
		shift
		timeout=$1
		shift
		;;
	*)
		command="$*"
		break
		;;
	esac
done

# prereqs
if [ -z "$command" ]; then
	usage
	exit 1
fi

# run

while true; do
	$command
	if [ $? -eq 0 ]; then
		break;
	fi
	sleep $timeout
done