I think what you want is '&' ie to background the task, which enables the rest of the script to continue. However if it's outputting to stdout, you should capture that.
nohup is used to allow a cmd issued from the cmd line to continue after you logout. Putting it all together looks like this
nohup myprog.sh >myprog.log 2>&1 &
NB: these 3 i/o channels are automatically assigned to every process
sdtin = 0
stdout = 1
stderr = 2