Check if host is a live bash script

!/bin/bash
 #
 TCP-ping in bash (not tested)
 HOSTNAME="$1"
 PORT="$2"
 if [ "X$HOSTNAME" == "X" ]; then
    echo "Specify a hostname"
    exit 1
 fi
 if [ "X$PORT" == "X" ]; then
    PORT="22"
 fi
 exec 3<>/dev/tcp/$HOSTNAME/$PORT
 if [ $? -eq 0 ]; then 
    echo "Alive."
 else
    echo "Dead."
 fi
 exec 3>&-