#!/usr/bin/perl -w
#rename.pl
$op = shift or die "Usage: rename expr [files]\n";
chomp(@ARGV = <STDIN>) unless @ARGV;
for (@ARGV) {
    $was = $_;
    eval $op;
    die $@ if $@;
    rename($was, $_) unless $was eq $_;
}

#converting all files in a dir to lowercase:
#rename.pl 'tr/A-Z/a-z/ unless /^Make/' *
#from the Perl Cookbook