How to get parent PID of a given process in GNU/Linux from command line?

Question

Resolved before asked: cat /proc/1111/status | grep PPid

faster: grep PPid status |cut -f2 like in time(for((i=0;i<1000;i++));do grep PPid status |cut -f2 >/dev/null;done); wonder if there is something even faster? — Aquarius Power, Aug 09 '14 at 23:55
@AquariusPower Since you ask, fgrep is faster than grep. fgrep PPid status |cut -f2 — jbo5112, Feb 18 '16 at 22:46
sed is way faster than grep and cut: sed -rn '/PPid/ s/^.*:\s+// p' < status — Marian, Apr 25 '17 at 23:15
pid=3773234; while true; do pid=$(awk '/^PPid:/{print $NF}' /proc/$pid/status);printf "$pid\n"; if [ $pid -eq 1 ];then break;fi;done|tac — P...., Jun 19 '21 at 04:53

Dennis Williamson · Accepted Answer · 2015-09-02T20:01:47.793

139

Command line:

ps -o ppid= -p 1111

Function:

ppid () { ps -p ${1:-$$} -o ppid=; }

Alias (a function is preferable):

alias ppid='ps -o ppid= -p'

Script:

#!/bin/sh
pid=$1
if [ -z $pid ]
then
    read -p "PID: " pid
fi
ps -p ${pid:-$$} -o ppid=

If no PID is supplied to the function or the script, they default to show the PPID of the current process.

To use the alias, a PID must be supplied.

edited Sep 02 '15 at 20:01

answered Jun 08 '10 at 11:21

Dennis Williamson

108,309

1

The = sign is not necessary, at least on OS X 10.8.2. – jtbandes Jan 09 '13 at 19:04
7

@jtbandes: The equal sign as used here suppresses the output of the header line (Linux and OS X). – Dennis Williamson Jan 09 '13 at 21:08
1

prefer alias if you want any shell auto-complete to still work – smac89 Dec 07 '20 at 23:59
Auto-completion of function names works just fine for me. – Dennis Williamson Jun 27 '22 at 21:36

kenorb · Answer 2 · 2019-07-23T09:02:03.123

20

To print parent ids (PPID) of all the processes, use this command:

ps j

For the single process, just pass the PID, like: ps j 1234.

To extract only the value, filter output by awk, like:

ps j | awk 'NR>1 {print $3}' # BSD ps
ps j | awk 'NR>1 {print $1}' # GNU ps

To list PIDs of all parents, use pstree (install it if you don't have it):

$ pstree -sg 1234
systemd(1)───sshd(1036)───bash(2383)───pstree(3007)

To get parent PID of the current process, use echo $$.

edited Jul 23 '19 at 09:02

answered Feb 19 '16 at 21:31

kenorb

25,417

1

pstree is the nicest one I've seen here. – sudo Sep 08 '17 at 00:33
ps j is great because it's available on many distros and is easily composable – Connor McCormick Jul 22 '19 at 20:58

score 15 · Answer 3 · answered Jan 31 '13 at 20:32

15

This is one of those things I learn, forget, relearn, repeat. But it's useful. The pstree command's ‘s’ flag shows a tree with a leaf at N:

pstree -sA $(pgrep badblocks)
systemd---sudo---mkfs.ext4---badblocks

answered Jan 31 '13 at 20:32

user194394

151

What about ps f? – Alex78191 Apr 03 '20 at 18:32
@Alex78191 why do you ask? What about it? It does something completely different to what the question asked. – nyov May 26 '20 at 13:28

score 14 · Answer 4 · edited Mar 16 '15 at 06:17

14

Parent pid is in shell variable PPID, so

echo $PPID

edited Mar 16 '15 at 06:17

Giacomo1968

55,001

answered Sep 24 '12 at 11:55

Ivan Novotny

149
1
2

3

Yes, but 1. I want parent pid of other process, 2. I want to be able to traverse all ancestors to init. – Vi. Sep 24 '12 at 12:37
4

On the other hand, using $PPID did just solve the problem I had which Google suggested this page as an answer to. – Paul Whittaker Sep 24 '12 at 15:58

score 10 · Answer 5 · answered Jun 08 '10 at 09:44

10

Read /proc/$PID/status. Can be easily scripted:

#!/bin/sh
P=$1
if [ -z "$P" ]; then
    read P
fi
cat /proc/"$P"/status | grep PPid: | grep -o "[0-9]*"

answered Jun 08 '10 at 09:44

Vi.

17,175

3

grep '^PPid:' /proc/$1/status | grep -o '[0-9]*' is all you need. (It is very uncommon for Unix tools to do the if [ -z ]; then read thing.) – u1686_grawity Jun 08 '10 at 11:12
@grawity It helps do do things like echo $$ | ppid | ppid | ppid – Vi. Jun 09 '10 at 13:04
3

UUOC useless use of cat – Felipe Alvarez Nov 25 '14 at 00:26
@FelipeAlvarez, My hands are not used to type < /some/file grep | grep | .... – Vi. Nov 25 '14 at 00:29
2

What about grep /some/file – Felipe Alvarez Nov 25 '14 at 00:35
Thanks for this answer, it helped me on an embedded system that only had one flag for ps (-w for wide output) so all of the answers using ps did not work for me. Thanks! – Citizen Kepler May 05 '16 at 00:37

score 5 · Answer 6 · edited Mar 16 '15 at 06:17

5

On Linux:

ps hoppid $thatprocess

edited Mar 16 '15 at 06:17

Giacomo1968

55,001

answered Oct 21 '14 at 17:30

jthill

161
1
3

score 3 · Answer 7 · answered Oct 19 '14 at 20:08

3

$ ps -p $(ps -p $(echo $$) -o ppid=) -o comm=
    tmux

A little bit more complex example that checks the command of a parent that started current process Change comm= to cmd= to see full command

answered Oct 19 '14 at 20:08

sebastian_t

143

Useless use of echo? ;) – bobbogo Oct 12 '17 at 10:21
It is actually required on some terminals. To be honest I don't remember exactly but it actually solved a problem. :D – sebastian_t Oct 13 '17 at 07:08

score 2 · Answer 8 · edited Jan 10 '14 at 15:45

2

Run top with whatever options you want, like -u username and -p PID.

And while top is working press f, it shows a list of options you want to display in top output, and the displayed parameters will be shown in CAPITAL letters and the parameters which or not displaying will be shown in small letters.

So by entering the letter before the parameter you can enable or disable it. For parent process ID you have to enter b and then press Enter, it'll display the PPID in top output.

edited Jan 10 '14 at 15:45

Kevin Panko

7,366

answered Nov 23 '12 at 12:21

Praveen S.

21
1

1

It is to be used non-interactively. I already know that in htop you can configure PPID column. – Vi. Nov 23 '12 at 13:49

score 1 · Answer 9 · edited Aug 30 '21 at 21:25

1

all parent processes of a pid

I came here when I was trying to find "all parent processes of a pid". I ended up making my own recursive function to do it.

pid_lineage.sh

#!/bin/bash -eu
main(){
  ps --pid ${1:-$$} --no-headers --format pid,ppid,args | 

    (
      read pid ppid args
      echo -e "$pid\t$args"
      [[ $pid -gt 1 ]] && main $ppid
    )
}
main "$@"

edited Aug 30 '21 at 21:25

John Karahalis

103

answered Oct 30 '19 at 21:51

Bruno Bronosky

1,955

@John-Karahalis I appreciate your edit. It was rejected by 2 other reviewers, but I agree and usually use long options to save readers time having to look up the meaning of cryptic flags. Thanks! – Bruno Bronosky Aug 30 '21 at 21:28

score 1 · Answer 10 · answered Sep 12 '13 at 06:18

1

Here is a quick solution that should also work:

ps $$

answered Sep 12 '13 at 06:18

Gevork Palyan

79

That doesn't give the parent PID which is what the OP asked for. – Dennis Williamson Sep 24 '13 at 19:35

How to get parent PID of a given process in GNU/Linux from command line?

10 Answers10

all parent processes of a pid

pid_lineage.sh