PHP Directories Getting and Setting File Timestamps

PHP Directories

Getting and Setting File Timestamps

Problem

You want to know when a file was last accessed or changed, or you want to update a file’s access or change time; for example, you want each page on your website to display when it was last modified.

Solution

The fileatime(), filemtime(), and filectime() functions return the time of last access, modification, and metadata change of a file, as shown:

       $last_access = fileatime('larry.php');

       $last_modification = filemtime('moe.php');

       $last_change = filectime('curly.php');

Update a file’s modification time with touch(). Without a second argument, touch() sets the modification time to the current date and time. To set a file’s modification time to a specific value, pass that value as an epoch timestamp to touch() as a second argument. This example changes the modification time of two files without changing their contents:

       touch('shemp.php');                  // set modification time to now

       touch('joe.php',$timestamp); // set modification time to $timestamp

Discussion

The fileatime() function returns the last time a file was opened for reading or writing. The filemtime() function returns the last time a file’s contents were changed. The filectime() function returns the last time a file’s contents or metadata (such as owner or permissions) were changed. Each function returns the time as an epoch timestamp.

This code prints the time a page on your website was last updated:

print "Last Modified: ".strftime('%c',filemtime($_SERVER['SCRIPT_FILENAME']));