Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This is an output from pstree

enter image description here

In the picture you can see the marked boxes in which the processes are multiplied by a number? What is this number?

I had a doubt that it is the number of instances but in that case when I only have 7 Firefox tabs, why is it showing 31.

Moreover when I open libre office (or|and)any of its singly or simultaneously components the number 5 and 2 remain the same.

Could somebody please explain to me what the numbers are and If we assume those are different instances the is it possible to kill a single instance without loosing others

share|improve this question
Threads (processes that share the same memory space) – Michael Martinez Mar 12 '14 at 19:29
ya I was confusing process and threads – Stormvirux Mar 13 '14 at 2:37
up vote 6 down vote accepted

The "multiplied by a number" means there are several copies of the program running. Some programs (like Firefox and LibreOffice you mention) run several processes or threads, and will thus show up several times.

Note that a process is an instance of a running program, so you can't kill an instance of a process (as the subject asks). You can kill a process, i.e., shut it down. Best way to do it is to just close it's window. There are more drastic measures that can be taken, but they should be used only as last resort.

share|improve this answer

Directly from man pstree:

Child threads of a process are found under the parent process and are shown with the process name in curly braces

So, these are threads. An application can use threads for any number of tasks (usually at least GUI is in a separate thread, plus everything that needs to be concurrent).

Killing a single instance? Use kill on the PID of the process. PID is the only unique identifier that refers specifically to a single process, regardless of its name. Use pidof to translate a name to a list of PIDs, ps to list processes (ps aux is a good way of printing all of them, together with metadata), htop (or even the ordinary top) for interactive listing.... for GUI applications, there's xkill that kills with a click. You have many options :)

share|improve this answer

it is processes and threads, if you do pstree -p it will show you all the thread ids and expand the tree at the same time rather than putting the multiplier in.

You'll see similar is you do ps w -eL it will show you the PID (process ID) and LWP (Thread ID) which should make it seem slightly less murky.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.