Tools to extract unique emails from text files. Ex: php extract-emails.php -f text.txt -o emails.txt

extract-emails.php

<?php
/* Tools to process end extract log data from text files 
* Ex: php extract-emails.php -f text.txt -o emails.txt
*/
function extract_emails ($from_text = "")
{
	$emails = [];
	if(!empty($from_text)) {
		$res = preg_match_all(
			"/[a-z0-9]+([_\\.-][a-z0-9]+)*@([a-z0-9]+([\.-][a-z0-9]+)*)+\\.[a-z]{2,}/i",
			$from_text,
			$matches
		);
		if($res) {
			foreach(array_unique($matches[0]) as $email) {
				$emails[] = strtolower($email);
			}
		}
	}
	return $emails;
}

$options = getopt("f:o:");
if(!isset($options['f']) || !file_exists($options['f'])) {
	exit("Error: Cannot open file!");
}

if(!isset($options['o'])) {
	exit("Error: Cannot create output file!");
}

// Extract data
$file_content = @file_get_contents($options['f']);
if(empty($file_content)) {
	exit("Error: No email addresses found!");
}

$emails = extract_emails($file_content);

if(!$emails) {
	exit("Error: No email addresses found!");
}

@file_put_contents($options['o'], implode("\r\n", $emails));