ifemi: hopefully that's not a homework (if it is, read the posting rules and some other threads/posts about this matter).
In case it is homework, state so, tell what you've done so far, what the culprit is and expect no more than clues (if somebody has time) and hints, and that you are going to have to do it yourself - that's what a homework is. In troublematic situations you should be contacting your teacher/tutor rather than ask for a ready answer. In any case, make a new thread about it, don't ask in somebody else's thread - that's called "stealing a thread".
In case it's not homework, it's ok to say it too. Don't lie
And anyway, start a new thread - read the above.
EDIT: hint: linuxcommand.org