I have to make list about how much user has used space in common "\\server\user" directory.

Every user have unique private directory structure, like
\\server\user\user1\
\\server\user\user2\
\\server\user\user3\ and etc.

Result would be like:
user1 used space: 386116234 bytes
user2 used space: 331232141 bytes
user1 used space: 4523512 bytes

Would some specialist help me modify below scipt, in current version I must specify what dir im calculating:
******
break on cls
$tempfile = "c:\temp\kix.tmp"
$dir = "c:\"
if exist("$dir") = 1
? "Reading $dir...... Please wait."
shell '%comspec% /c diruse "$dir" | find /i " total" > $tempfile'
$nul = open(1,$tempfile,2)
$data = readline(1)
$dirsize = ltrim(substr($data,1,13))
? 'The size of "$dir" = $dirsize bytes'
else
? "can't find $dir"
exit
endif
******

Thank you for your help
Henry