Check available domain names with this convenience tool.

domainChecker.sh

#!/bin/bash

# takes one argument as domain name and checks if this domain is registered.
#
# usage:
# sss google.com
#

function sss()
{
  if [ $# -eq 0 -o -z "$1" ]; then
    echo "You must provide a domain name."
    return
  fi

  if [ $(whois "$1" | grep -i 'registrant:' | wc -l) -ge "1" ]; then
    echo TAKEN;
  else
    echo AVAILABLE;
  fi
}

Unfortunately, whois is not very consistent in its results from different tld. Changing the script to use grep instead of exit code.