#!/usr/bin/perl -w

use strict;

my ($oldpat, $newpat);
my ($oldname, $newname);

$oldname = 'foo-64-bar';   # would normally be read from stdin

# basic substitution
$newname = $oldname;
$newname =~ s/-([0-9]+)-/_$1_/;
print "static patterns: $oldname becomes $newname\n";

# the same, but with the patterns in variables
$oldpat = '-([0-9]+)-';
$newpat = '_$1_';

$newname = $oldname;
$newname =~ s/$oldpat/$newpat/e;
print "variable patterns: $oldname becomes $newname\n";