I'm sure 'u' know about how to use the getpwnam() function, which will help 'u' find your Linux account information. As for the rest?

Looks like you've got a lot of work left to do!

Congratulations on using CGI.pm though. That can't hurt.

Update: I do hope that this form is being submitted over HTTPS and not plain HTTP. Otherwise, those who use it will surely be hacked, since their shell password is transmitted as plain-text.