What is the difference between a job and a process in Unix ? Can you please give an example ?
A Process Group can be considered as a Job. For example you create a background process group in shell:
$ find $HOME|sort &
[1] 2668
And you can see two processes as members of the new process group:
$ ps -p 2668 -o cmd,pgrp
CMD PGRP
sort 2667
$ ps -p "$(pgrep -d , -g 2667)" -o cmd,pgrp
CMD PGRP
find /home/juergen 2667
sort 2667
You can can also kill the whole process group/job:
$ pkill -g 2667