If you are using Apache then the htCheckPassword command in the htpasswd module at CPAN enables you to check whether an Apache password is correct. In general, however, the Apache password and the Unix password will not be the same.

It is possible to configure Apache so that it uses Unix Ids and passwords for authentication, but most experts strongly recommend against doing so.

So the answer is yes, it is at least possible.

# Check that a password is correct $pwdFile->htCheckPassword("zog", "password");