[imp] How to show space used by emails?

[Alex Gavrila]

Hi all.

I use Redhat 8 with 
  a.. Horde: 2.2.7 
  b.. IMP: 3.2.7 (run IMP tests) 
  c.. Turba: 1.2.3 
  d.. Kronolith: 1.1.3 
  e.. Mnemo: 1.1.3 
  f.. Nag: 1.1.2 
And with PHP 4.2.2.

I want that Imp show somehow current username and space used by emails in /var/spool/mail/"NameOfUser".

I played with a code I found on SquirrelMail:

echo "<font size=2>Space Used: </font>";
system("du -hs /var/spool/mail/$username | awk '{print $1}'");

but I didn't managed to resolve what I want.

How can I modify the code and where to put it to show what I want?

Thanks,
Alex.