I just installed Rakarrak, connected my guitar to the input of the computer and there is sound from the guitar. But I don't see any effects processing from Rakarrak. I just hear the plain sound from the guitar still. Am I missing something? Rakarrak starts normally without any errors and I can turn on/off different sections of it. I effects on by clicking on FX ON at the top left hand side.
I have jackd installed on my machine, I use Centos 5, please let me know how exactly this app has to be used.
You need to connect the inputs and outputs to jack. This can be done on the command line, but I personally like using jack with qjackctl. You must have jackd running successfully for rakarrack to start up, so you obviously have that part working correctly. Jack just needs to know what signal it should be feeding into rakarrack, and where to feed rakarrack's output when it has finished its processing.
It sounds like jack is routing your guitar directly from line in to line out on your sound card. If you're getting sound into rakarrack, you'll see the VU meter bars bouncing. If rakarrack's output is correctly plugged into jackd, then you'll definitely be hearing the FX.
In summary, I think your problem is with jack, and not with rakarrack. Install qjackctl and use the signal routing tool to get the inputs and outputs going to the right place. Disconnect any direct connections from capture to line out.
I hope you find that helpful.