(1). Since background job can still run even if the user logs out, what's the point of using nohup and screen?
(2). What is the difference between CTRL+Z and stop to suspend a background job? There is another command "stop" which stops a background job. This doesn't kill the job, but it will not continue executing until it is restarted. I wonder what is the difference between "stop" and CTRL+Z? for "stop", see http://www.ece.osu.edu/computing/background_jobs.html#commands
(3). to make a background job noninteractive, is this correct?
command <<inputfile> ><outputfile>
What if I want to append the output to an existing file while keep the job background?
Thanks and regards!