I want to view a .lin file with the BBO-client, installed in wine under linux, when I click a link to a .lin file in Firefox.

Create a script which is used as a launcher in Firefox – example

par=`winepath -w “$*”`
wine “$loc” “$par”
exit 0

Be sure to make it executable chmod +x
Next time you click a .lin file in Firefox, Open With – locate – and check “Do this from now on..”.