#!/usr/bin/perl

use strict;
use warnings;

my $f = shift;

if ($f =~ m[^s/])
{
    $f = eval "sub { $f }";
}
else
{
    my $re = qr/$f/;
    my $to = shift;

    $f = eval "sub { s/\$re/$to/ }";
}

for (@ARGV)
{
    my $o = $_;
    $f->();
    if ($o ne $_)
    {
        print "rename $o, $_\n";
        rename $o, $_;
    }
}