Simple bash script to test whether a port is open or closed. It's a good alternative to telnet.

open-port-test

#!/bin/ash

NETCAT="netcat"

if [[ "$2" == "" || "$1" == "" ]]; then
  echo "Invalid port or ip!"
  echo "USAGE: $0 ip port"
  exit 0
fi

type "$NETCAT" >/dev/null 2>&1 || \
	{ echo >&2 "I require netcat but it's not installed.  Aborting."; exit 1; }

"$NETCAT" -z "$1" "$2" &> /dev/null && \
	echo "Port $2 is Open" || \
	echo "Port $2 is Closed!"