Obtruse_Man4

I'm trying to incorporate a secure download script into an already coded file management system. I want the url path to be download.php?file=, and then the file name. The file name is taken from the variable .$file. How do I add the variable onto the end of the url? What I currently have below doesn't seem to work. It passed the error:

[PHP]$file_string = "<li>Get file: <a href="download.php?file=.$file."> ".$file."</a> (".human_file_size(filesize($file)).")</li>";[/PHP]

__________________
"I have many layer-eight problems in my life, including myself."