Perl5 リファレンス

       rename OLDNAME,NEWNAME
               Changes the name of a file; an existing file
               NEWNAME will be clobbered.  Returns true for
               success, false otherwise.

               Behavior of this function varies wildly depending
               on your system implementation.  For example, it
               will usually not work across file system
               boundaries, even though the system mv command
               sometimes compensates for this.  Other
               restrictions include whether it works on
               directories, open files, or pre-existing files.
               Check the perlport manpage and either the
               rename(2) manpage or equivalent system
               documentation for details.