Bulk replace language strings in Elgg

start.php

<?php

elgg_register_event_handler('upgrade', 'system', 'build_language_file', 999);

/**
 * Rename:
 *  - Friends > Contacts
 * 
 * @global array $GLOBALS
 */
function build_language_file() {

	global $GLOBALS;

	$language = 'en';

	_elgg_services()->translator->reloadAllTranslations();
	
	$translations = $GLOBALS['_ELGG']->translations[$language];

	$map = [
		'friendships' => 'contacts',
		'friendship' => 'contacts',
		'friends' => 'contacts',
		'friend' => 'contact',
	];

	$output = [];

	foreach ($map as $original_str => $target_str) {
		foreach ($translations as $key => $translation) {

			$original_translation = $translation;
			$translation = str_replace(strtolower($original_str), strtolower($target_str), $translation);
			$translation = str_replace(ucfirst($original_str), ucfirst($target_str), $translation);

			if ($original_translation != $translation) {
				$output[$key] = $translation;
				$translations[$key] = $translation;
			}
		}
	}

	$file = fopen(__DIR__ . "/translations.php", 'w');
	$contents = var_export($output, true);
	fwrite($file, "<?php\r\n\r\nreturn $contents;\r\n");
	fclose($file);
}