Master Linux ps Command: Powerful Tips for Process Monitoring & Reporting

1. What is ps?

To monitor and control processes you first need to know their current state; the ps command displays a snapshot of running processes, showing which are active, terminated, zombie, or consuming excessive resources.

ps shows a snapshot of process status, not a continuous stream. For real‑time monitoring use top.

Basic options:

-A: show all processes (same as -e)

-a: show processes attached to terminals, including those of other users

-u: display information in a user‑oriented format

x: usually combined with -a to list processes without a controlling terminal

Output format options:

l: long, detailed listing of each PID

j: jobs format

-f: full‑format listing

2. What does ps output without parameters?

Running ps with no arguments displays four columns: PID, TTY, TIME, and CMD. The rows are not sorted.

3. How to display all current processes?

Use the -a option (all) and optionally x to include processes without a controlling terminal. $ ps -ax You can pipe the output to less for easier navigation.

4. How to filter by user?

Use -u followed by the username. Example for user pungki:

$ ps -u pungki

5. How to filter by CPU and memory usage?

Use the aux options to display comprehensive information: $ ps -aux | less Sort by CPU usage (descending):

$ ps -aux --sort -pcpu | less

Sort by memory usage (descending):

$ ps -aux --sort -pmem | less

Combine both sorts and show the top 10 results:

$ ps -aux --sort -pcpu,+pmem | head -n 10

6. How to filter by process name or PID?

Use -C followed by the command name. Example for the getty process: $ ps -C getty For more detail add -f:

$ ps -f -C getty

7. How to filter by thread?

Use -L with the PID of the process whose threads you want to list:

$ ps -L 1213

8. How to display processes as a tree?

Use the -axjf options for a tree‑like view, or the dedicated pstree command:

$ ps -axjf

$ pstree

9. How to show security information?

Display who is logged in and what they are running:

$ ps -eo pid,user,args

-e

shows all processes; -o controls the output columns (PID, User, Args).

10. How to format output for processes created by root?

Filter by real and effective UID of root and use the user‑oriented format:

$ ps -U root -u root u

11. How to monitor processes in real time with ps?

Combine ps with watch to refresh every second:

$ watch -n 1 'ps -aux --sort -pmem, -pcpu'

Limit to the top 20 lines:

$ watch -n 1 'ps -aux --sort -pmem, -pcpu | head 20'

Filter for a specific user (e.g., pungki) while watching:

$ watch -n 1 'ps -aux -U pungki u --sort -pmem, -pcpu | head 20'

12. Conclusion

The ps command is versatile for generating custom reports; it is installed by default on all Linux distributions. Remember to consult man ps for a complete list of options.

Source: https://juejin.im/post/5bf9213ce51d452237153c5c