Where art thou 'rename'

[Romain Kang]

Here's something posted to USENET ca. 1991.  I've been carrying around
my own copy ever since:

#! /usr/local/bin/perl
$op = shift;
for (@ARGV) {
    $was = $_;
    eval $op;
    die $@ if $@;
    rename($was,$_) unless $was eq $_;
}