Including date in file path

Hey all,

Thanks for this great forum.  I've learned a lot.

What I'm trying to do is create a php script that will select a folder based on the date.  For example, this is the original code:

$file = '/var/www/html/public_html/svsshc/'.$_REQUEST['id'].'.png';

the folder the .png files will be in, for example, is:

/var/www/html/public_html/svsshc/2014-01-07

I tried doing this but it did not work properly:

$file = '/var/www/html/public_html/svsshc/'$_date'/'.$_REQUEST['id'].'.png';

I apparently don't have a very good grasp on how the php date function works.  Any suggestions on what to do?

Thank you!