to add to the existing answers... consult the docs

>perldoc -q rename a file
Found in perlfaq5.pod
  How can I reliably rename a file?

            Well, usually you just use Perl's rename() function. That may
            not work everywhere, though, particularly when renaming files
            across file systems. Some sub-Unix systems have broken ports
            that corrupt the semantics of rename()--for example, WinNT does
            this right, but Win95 and Win98 are broken. (The last two parts
            are not surprising, but the first is. :-)

            If your operating system supports a proper mv(1) program or its
            moral equivalent, this works:

                rename($old, $new) or system("mv", $old, $new);

            It may be more compelling to use the File::Copy module instead.
            You just copy to the new file to the new name (checking return
            values), then delete the old one. This isn't really the same
            semantically as a real rename(), though, which preserves
            metainformation like permissions, timestamps, inode info, etc.

            Newer versions of File::Copy exports a move() function.

~Particle *accelerates*