matcher '(.*@.*)' '$1' < input_file_with_emails

matcher.php

#!/usr/bin/env php
<?php
define('DEBUG', false);

class Logger
{
	private $fp;

	public function __construct($fp) {
		$this->fp = $fp;
	}

	public function debug($msg) {
		if (DEBUG) $this->log("debug: $msg");
	}

	public function error($msg) {
		$this->log("error: $msg");
	}

	public function warning($msg) {
		$this->log("warning: $msg");
	}

	public function log($msg) {
		fputs($this->fp, trim($msg) . "\n");
		fflush($this->fp);
	}
}

$fp = fopen('php://stderr', 'w');
$log = new Logger($fp);

if (count($argv) !== 3) {
	$log->log("usage: {$argv[0]} 'pattern' 'output'");
	exit;
}

$pattern = $argv[1];
$output = $argv[2];

$fp = fopen('php://stdin', 'r');
if (!$fp) {
	$log->error('unable top open stdin');
	exit;
}

while ($line = fgets($fp)) {
	preg_match_all($pattern, $line, $matches, PREG_SET_ORDER);
	foreach ($matches as $match) {
		$log->debug('Found match: ' . print_r($match, true));
		$outfmt = $output;
		$replkeys = array();
		$replvals = array();
		foreach ($match as $key => $val) {
			$replkeys[] = "\$$key";
			$replvals[] = $val;
		}
		$log->debug('Replacing keys: ' . print_r($replkeys, true));
		$log->debug('Replacing vals: ' . print_r($replvals, true));
		echo str_replace($replkeys, $replvals, $outfmt) . "\n";
	}
}

fclose($fp);