How do I list the process in a Unix based system which are running in background?
The following are options that I'm aware of, but they may not be appropiate.
a. using
ps -ef
, and getting records of processes for which STATUS='S'(uninterruptible sleep)
b. using
jobs -l
, and filtering records that end with "&"
Please advise.
Regards,
Kumarjit.
then you have to define what you understand under "background", because ps -ef does what you asked for.
Processes that runs without any inputs required from the terminal are background processes. That's what I know of.
But how exactly would I be listing them, is yet to be discovered. 
Please help.
Regards.
it's obviously wrong definition. look at the better one - Background process - Wikipedia, the free encyclopedia
if you run e.g. ps -ef you see TTY column. If you see in this field something like ?, the process has no attached terminal. It would be pass to your definition of a background process.
For processes without an attached terminal:
ps -t -
See the man ps (linux) manpage for more information.
My question is pretty clear.
LIST ALL PROCESSES THAT ARE CURRENTLY RUNNING IN THE BACKGROUND
and for that, is it possible to use the
ps -ef
command, and list records where STAT='S'(interruptible sleep)?
What does the STAT='S' signify?(what I was able to find out from other resources is that a process with STAT='S' is WAITING FOR A EVENT TO COMPLETE, mainly I/O)
So how would only the background processes have this status? Even foreground processes can be in the 'S'(wait) state if it waits for other events to complete.
I think judging processes based on the status column is not acceptable when identifying background processes.
Regards.