A better explanation:For file $file and UNIX time stored in vars $access and $modified- change only access time\touch($file, \filemtime($file), $access);- change only modified time\touch($file, $modified, \fileatime($file));- change both access and modified time\touch($file, $modified, $access);Seeing the results://use a session cookie stored in a custom folder$file = '/var/www/test_com/session/sess_qfn587cudfpgsijm1bs4d81s75';echo 'stats for sess_qfn587cudfpgsijm1bs4d81s75<br/>';\clearstatcache();echo 'access: '.\date("Y-m-d H:i:s", \fileatime($file)).'<br/>';echo 'modified: '.\date("Y-m-d H:i:s", \filemtime($file)).'<br/>';echo 'change access to now, modified +1 hour<br/>';\touch($x, \filemtime($file)+3600, time());\clearstatcache();echo 'access: '.\date("Y-m-d H:i:s", \fileatime($file)).'<br/>';echo 'modified: '.\date("Y-m-d H:i:s", \filemtime($file)).'<br/>';Notice the double call to clearstatcache()!