What worked for me was this.
Based on Installing 3.5.beta2 over 3.4 - not upgrading?
http://forum.subsonic.org/forum/viewtopic.php?t=1291
1. stop the subsonic server.
The easiest method for me as a Windows user trying to figure out Linux was the bull-in-the-china-closet method.... go into the system monitor and kill all of the java processes that were running (two for me).
Second easiest was to create a new file and paste the script from the start/stop shell script topic (link below) into it (need to modify the location of the script file referenced in the file for the standalone version), make it executable, and then run it from a terminal.
I suppose a third option would be to enter the desired command as shown in the script directly into a terminal (hope you like typing).
There are probably several other ways to do it, most likely more graceful. (If I was doing it on Windows, I would write a vbscript that toggles the status and displays a prompt with the result.... not sure what the linux equiv is.... don't say typing in terminal cuz that ain't equivalent to clickin an icon... maybe a couple extra lines in the given script could generate a prompt and do the toggle logic)
Simple start/stop shell-script:
http://forum.subsonic.org/forum/viewtopic.php?t=1546
ok, now for the real stuff.
2. go to /var/subsonic
3. rename jetty folder to something else (jetty_)
4. go to /var/subsonic/standalone
5. extract the files from the downloaded archive (subsonic-3.7.beta1-standalone.tar.gz) into /var/subsonic/standalone
6. execute the subsonic.sh file
7. point your web browser to
http://servername:8080
This should keep all of your settings and database which I believe are in the /var/subsonic/db folder.
You can delete the old jetty folder if you're sure you won't need it any more.