Apart from the other comments, using grep with user-supplied data as the pattern (as your $uname variable may be) is evil and should be avoided, because it opens the possibility to all sorts of mischief. What if $uname contains regular expression metacharacters? What if it contains one of the magic forms that allow you to execute arbitrary Perl code? I would also suggest using hashes for storing the user names. Makes your code a lot cleaner and makes it much easier to test whether a user is already there.

For some related discussion, see the FAQ How can I tell whether a list or array contains a certain element?

--ZZamboni