#!/usr/bin/perl

$string = "a\@b.c\n";
$string =~ s#\Qa@b.c\E#email-address#g;
print $string;

$string2 = "a\@b.c\n";
$string2 =~ s#a\@b\.c#email-address#g;
print $string2;

$string3 = "a\@b.c\n";
$qm3 = quotemeta('a@b.c');
$string3 =~ s#$qm3#email-address#g;
print $string3;

##</code><code>##

a@b.c
email-address
email-address