[Zope] location of tmp-file while uploading a file

[markus]

hi,

while uploading a file through the ZMI, i'd tried to locate this file on
the filesystem on my linux box.
with 'df' i saw that the space on /var was used. i've tried to locate
the file, but i've had no success.
then i used a simple "du -sb /var > out1 && sleep 10 && du -sb /var >
out2 && diff -a out1 out2" to find the file. but there was no diff!! but
meanwhile /var used about 10MB more space. 

any help?

markus