bash wget - function check is valid file at url before downloading

validate_url.sh

#!/usr/bin/env bash
# simple function to check http response code before downloading a remote file
# usage:
# if `isValidUrl $url >/dev/null`; then dosomething ; else echo "url does not exist!" ; fi

function isValidUrl() {
    if [[ `wget -S --spider $1 2>&1 | grep 'HTTP/1.1 200 OK'` ]] ; then
        echo "true"
    fi
}