Making string all lowercase...

[cgm225]

I have a variable containing a string which I ultimately use to name a directory after.  Currently, I trim and strip it down, removing bad characters, spaces, etc.  However, I also want to make the string all lowercase.  How could I modify the following to do that?

 

$directory = trim(preg_replace("/[^a-zA-Z0-9s]/", "",stripslashes($directory)));

 

 

 

[craygo]

strtolower();