Create a JSON object containing the sha256 hash of each photo in a directory. The main usage is to identify and quarantine or remove duplicates.

hasher.php

<?php

// hardcoded files created: pics.list, error.log

// config
$hashf = 'hash.json';

// globals
$movetotrash = true; # you can change this
$needskip = false; # must leave false

// functions
function name($picpath) {
	return preg_replace("/^.*\//", "", $picpath);
}

function sha256($picpath) {
	return hash('sha256', file_get_contents($picpath));
}

function readhash($hashf) {
	return json_decode(file_get_contents($hashf), true);
}

function add2hash($hashdata, $data) {
	if (inhash($data['hash'], $hashdata)) {
		$old = $data['path'];
		$new = "trash/" . (preg_replace("/\//", "", filemtime($data['path']) . (rand(0, 999)) . '/' .  $data['path']));
		$error = "{$data['path']} EXISTS AS {$hashdata[$data['hash']]['path']}. ";
		if ($GLOBALS['movetotrash']) {
			$error .= "mv {$old} {$new}\n";
			rename($old, $new);
		}
		print($error);
		$GLOBALS['needskip'] = true;
		// TODO: here we need to move the cursor down and not up because these errors should be printed and not hidden
		//       http://www.tldp.org/HOWTO/Bash-Prompt-HOWTO/x405.html
		file_put_contents("error.log", "{$error}\n", FILE_APPEND);
	} else {
		$hashdata[$data['hash']] = $data;
	}
	return $hashdata;
}

function writehash($hashf, $hashdata, $data=null) {
	if (!is_null($data)) {
		$hashdata[$data['hash']] = $data;
	}
	return file_put_contents($hashf, json_encode($hashdata));
}

function inhash($hash, $hashdata) {
	return array_key_exists($hash, $hashdata);
}

function exists($picpath, $hashf) {
	return inhash(sha25($picpath), readhash($hashf));
}

function console($numpics, $curindex, $msg) {
	$percent = 100 * round(intval($curindex) / (intval($numpics) - 1), 2);
	$of = ($curindex + 1) . " of {$numpics}";
	if ($GLOBALS['needskip']) {
		$GLOBALS['needskip'] = false;
	} else {
		system('tput cuu1');
		system('tput el');
	}
	print("{$percent}% finished : {$of} : {$msg}\n");
}

function picslist() {
	`find . -iname '*.jpg' > pics.list`;
}

function initerrorlog() {
	file_put_contents('error.log', '');
}

function inithash($hashf) {
	file_put_contents($hashf, '{}');
}

function cleanup() {
	unlink('error.log');
	unlink($hashf);
}

function writeall($hashf) {
	$pics = file('pics.list', FILE_IGNORE_NEW_LINES);
	$hashdata = readhash($hashf);
	$numpics = count($pics);
	foreach($pics as $k=>$picpath) {
		$name = name($picpath);
		console($numpics, $k, $picpath);
		$hash = sha256($picpath);
		$hashdata = add2hash($hashdata, array(
			"hash" => $hash,
			"name" => $name,
			"path" => $picpath,
			"size" => filesize($picpath)));
	}

	writehash($hashf, $hashdata);
}

function initdirs() {
	if (!file_exists("trash")) {
		mkdir("trash");
	}
}

// actions
$action = readline("Enter action: <init|clean|add2hash> ");

if ($action === 'init') {

	initerrorlog();
	inithash($hashf);
	initdirs();
	exit();

} else if ($action === 'clean') {

	cleanup();
	exit();

} else if ($action === 'add2hash') {

	picslist();
	if (!file_exists($hashf)) {
		inithash($hashf);
	}
	initerrorlog();
	writeall($hashf);
	exit();

}