Question

What are two methods to identify the PID number of the login shell?

A) ps command and grep command
B) ls command and cd command
C) rm command and cp command
D) cat command and chmod command

Answer 1

The two methods to identify the PID number of the login shell are ps command and grep command. So the correct option is A) ps command and grep command

Step-by-step explanation:

The ps command (process status) in Unix-like operating systems displays information about active processes. By using ps -p $$, where $$ represents the current shell's PID, you can directly retrieve the PID of the login shell. Additionally, you can use the grep command in combination with ps to filter out and display specific information. For instance, ps -ef | grep $$ fetches the PID associated with the current login shell.

The ps command provides a snapshot of currently running processes, including their PIDs, while grep filters and extracts specific data from the output of other commands. By combining these two commands, you can efficiently identify the PID number of the login shell in a Unix-based system. This method relies on leveraging the process status information (ps) and employing pattern matching (grep) to isolate and retrieve the PID associated with the active login shell process.

So the correct option is A) ps command and grep command.