Are you sure? I think I should clarify my situation. I have xampp on my USB stick for using at windows machines on the go. I have lampp on my linux-based machine, but I want to use the same /htdocs folder so the dbs stay the same whereever I am.
I'm a bit confused as to what you meant in the last post; here are the commands I have tried, non getting the job done.
ln -s /media/disk/xampp/htdocs/ /opt/lampp/
ln -s /media/disk/xampp/htdocs /opt/lampp
(the above two create a /htdocs link in my root lampp folder, what I expect should be the case. the bottom two give me /xampp, which it does not seem that any paths would follow. e.g. files point to /opt/lampp/htdocs/wiki, not /opt/lampp/xampp/htdocs/wiki)
ln -s /media/disk/xampp/ /opt/lampp/
ln -s /media/disk/xampp/ /opt/lampp/htdocs