New script that checks if a script is running

include/pidfile.php

@@ -0,0 +1,32 @@
+<?php
+class pidfile {
+	private $_file;
+	private $_running;
+
+	public function __construct($dir, $name) {
+		$this->_file = "$dir/$name.pid";
+
+		if (file_exists($this->_file)) {
+			$pid = trim(file_get_contents($this->_file));
+			if (posix_kill($pid, 0)) {
+				$this->_running = true;
+			}
+		}
+
+		if (! $this->_running) {
+			$pid = getmypid();
+			file_put_contents($this->_file, $pid);
+		}
+	}
+
+	public function __destruct() {
+		if ((! $this->_running) && file_exists($this->_file)) {
+			unlink($this->_file);
+		}
+	}
+
+	public function is_already_running() {
+		return $this->_running;
+	}
+}
+?>