Linux Process Management 4

Question 1

Which command displays the process tree showing parent-child relationships?

Accepted Answer

pstree

Answer

pstree displays running processes as a tree, visually showing parent-child relationships between processes.

Question 2

What does 'kill -0 PID' do?

Accepted Answer

Sends no signal but checks if the process exists and you can signal it

Answer

Signal 0 is never actually sent; it only checks whether the process exists and whether the caller has permission to signal it.

Question 3

What is the difference between foreground and background jobs in a shell?

Accepted Answer

Foreground jobs receive terminal input; background jobs do not

Answer

Foreground jobs have control of the terminal and receive keyboard input, while background jobs run without terminal control.

Question 4

Which command brings a background job to the foreground?

Accepted Answer

fg %1

Answer

fg %jobnumber brings the specified background job into the foreground and gives it terminal control.

Question 5

What does the /proc/PID/fd directory contain?

Accepted Answer

Symbolic links to all file descriptors opened by the process

Answer

/proc/PID/fd contains one symbolic link per open file descriptor, pointing to the actual file, socket, or pipe.

Linux Practice Test