An even easier way to get the process ID (PID) of your program is to do
ps -C [program name]
Then you can kill it if you want. Also, nohup [command] & just directs all output to nohup.out (the nohup part) and makes it run in the background (the &). To bring the program back from the background, you can type
and to see which programs you started with &, type jobs. Whew. Little process control tutorial there.