#!/bin/sh
# Selects a hopefully unused port in a given range and outputs it.
# Assumes that nothing else is racing to open a port in the same range.
low=$1
high=$2
	
used () {
	netstat --inet -n | grep '^tcp' | awk '{print $4}' | \
		cut -d : -f 2 | egrep -q "^$p$"
}

for p in $(seq $low $high); do
	if ! used; then
		echo $p
		exit
	fi
done

echo "Could not find free port between $low and $high"
exit 1