I have a file extension (.hgf) that I would like to associate with with a Java jar file. I'm running Ubuntu 11.11 and in Dolphin (the file manager GUI) I use "java -jar ~/Havannah/HGui/HGui.jar" as my 'open with' and clicking on hgf files in Dolphin will automatically run my HGui.jar program with the clicked file as input. When I try to do the same thing in Friefox with 'open with' I cannot get it to work. The file gets saved in /tmp but HGui never seems to run on it. I've tried various combinations of quotes, putting the command into a shell script, etc., but cannot seem to get the click and open behavior I would love to see. Thanks in advance for any suggestions you might have!