UNIX for Dummies Questions & Answers

if a particular log file logs different processes with their process ids and their paths and one of the process in particular is getting hung up while trying to perform a loop, how to identify which process is that and kill it

Um, ok, is "a paricular log file logs different processes with their process ids" looks like a red herring, so i'll read the question as follows:

"One of the process is getting hung up; how to identify which process it is and kill it".

Though it is sometimes possible to tell what a process is doing, it's really not possible to tell if it's "hung", due to a well known fundamental theorem of computing known as the Turing Thesis, aka, the Halting Problem.

So another way of approaching this problem is: has a particular process spent too much time running/using CPU cycles/consumed too much memory? Further, you need to distinguish such a process from others running on the same system. Can you further restrict the set of processes to its owner, or if it's connected to a terminal, or if it has a particular command-line name, or if it has a particular process as a parent?

Each variant of UNIX has a different set of process info available to the user, and thus, the ps command varies. So we also need to know which variant of unix you're using.