A simple PHP question

[weee]

I saw that line in a page that I need to update and I really would like to know what's the input of this line and what it does?

<?php $day_name = date("D"); echo ("$day_name\n"); ?>

[NogDog]

It's going to output the 3-character abbreviation of the current day of the week (Mon, Tues, Wed, etc.) followed by a newline character. It could be written a bit more simply as:

<?php echo date("D") . "\n"; ?>