How to find out what created a file

[Björn Lindström]

I've recently rented a jailed FreeBSD system, and have this little
problem:

Now and then, this file is created in my home directory:

-rw-r--r--  1 root users 6 May  1 20:20 /home/bkhl/-

The contents of the file is the string "xyzzy\n".

Now I never say "xyzzy", so I'm pretty sure I haven't set this up by
mistake.

To find out where this happens, how could I monitor this file name for
activity, to find out what command is creating it?

-- 
Björn Lindström <bkhl at elektrubadur.se>
http://bkhl.elektrubadur.se/