printing a children's full tree recursively in bash script

Question

sry for not being familiar with question conventions since im new here.

i want to write a script that prints the full children's tree recursively of a given pid.

i got so far as:

ps h -ef | awk '$3='$input_pid' {print $2}' | sort -n

but this is just for printing the immediate children of the given pid (sorted).

the question is: how can i summon the recursive function for every child-pid of the given pid?

thanks...

Does `pstree` do what you want ? – user9517 Feb 21 '16 at 12:21 — user9517, Feb 21 '16 at 12:21
`ps axf` might be your friend. – Jakuje Feb 21 '16 at 17:02 — Jakuje, Feb 21 '16 at 17:02

score 1 · Accepted Answer · answered Feb 22 '16 at 07:26

1

try this

pstree -p parent_process_ID

If you want only pid to be displayed

pgrep -P parent_process_ID

or the simpler and a detailed display.

ps auxfww | grep -v grep | grep process_name

answered Feb 22 '16 at 07:26

Gaurav Pundir

the command "pgrep -P parent_process_ID" works only when i use it out of the script. for example, when i run it on the pid 2 it prints me all the processes running from 1 to 32656. why is that? – N.R. Feb 24 '16 at 06:58
Because pid 2 belongs to kthreadd process, which is kernel threads and you will see lots of children for kthreadd process. try this command too **ps -f -p 2 --ppid 2** for kthreadd process and its children. And pgrep works in the script too, I am not sure why it is not working with your script. try giving complete path of pgrep ie **/usr/bin/pgrep**, it should work. – Gaurav Pundir Feb 24 '16 at 07:10
i made a mistake. the command "pgrep -P parent_process_ID" works perfect. thanx!!! – N.R. Feb 24 '16 at 11:41

1 Answers1