Adding blowup for if the arguments aren't specified

doBackup.sh

@@ -2,7 +2,7 @@
 hostname=$1;
 username=$2;
 password=$3;
-
+([ -z "$hostname" ] || [ -z "$username" ] || [ -z "$password" ]) && echo "all 3 arguments must be specified: hostname username password " && exit 1;
 csrf=$(curl -Ss --insecure --cookie-jar /tmp/$hostname-cookies.txt https://$hostname/diag_backup.php | sed -n 's/.*name=.__csrf_magic. value="\([^"]*\)".*/\1/p')
 csrf2=$(curl -Ss --insecure --location --cookie-jar /tmp/$hostname-cookies.txt --cookie /tmp/$hostname-cookies.txt --data "login=Login&usernamefld=$username&passwordfld=$password&__csrf_magic=$csrf" https://$hostname/diag_backup.php | sed -n 's/.*var csrfMagicToken = "\([^"]*\)".*/\1/p')
 curl -Ss --insecure --cookie /tmp/$hostname-cookies.txt --cookie-jar /tmp/$hostname-cookies.txt --data "Submit=download&donotbackuprrd=yes&__csrf_magic=$csrf2" https://$hostname/diag_backup.php > config-router-`date +%Y%m%d%H%M%S`.xml