This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Pipe the result through "grep", and use a regular expression that says "four characters, optionally followed by more." I'm assuming this is a school assignment, so I'm not going to actually type the command for you, but hopefully this is enough.