This shortcode will display the post’s last modified timestamp. By default it will display the timestamp in the date & time format that you specify in your blog settings.

If you wish to change it you can use the format=”” option to display the date and time any way you want. (Examples: May 4, 2010 6:41 pm or 2010/05/04 18:41 etc…)
Visit the php date() function page for information on different formats.

Just insert the following code to the bottom of your functions.php file.

function jason_moddate($atts) {
	global $post;
	extract(shortcode_atts(array('format' => get_option("date_format") . " " . get_option("time_format")), $atts));
	return date($format, strtotime($post->post_modified));
}
add_shortcode('moddate', 'jason_moddate');

Now you can use [moddate] anywhere inside your posts or pages:

This post was last modified on [moddate]

Will get you:

This post was last modified on May 5, 2010 2:08 am

Format Examples:

Display just the date:

[moddate format="Y-M-D"]
2010-May-Wed

Display just the time:

[moddate format="h:i:s a"]
02:08:40 am

Combine them together for a full timestamp:

[moddate format="Y-M-D h:i:s a"]
2010-May-Wed 02:08:40 am

Created on WordPress version 2.9.2