File::chmod is a utility that allows you to bypass system calls
or bit processing of a file's permissions. It overloads the
chmod() function with its own that gets an octal mode, a
symbolic mode, or an "ls" mode. If you wish not to overload chmod(),
you can export symchmod() and lschmod(), which take, respectively,
a symbolic mode and an "ls" mode.

WWW: http://search.cpan.org/dist/File-chmod/