Unix (and Linux) uses a process tree that gives a natural security, by simple inheritance of attributes.
The following ptree script shows it. It runs on all Linux flavors.
#!/bin/sh
# Solaris style ptree
[ -x /usr/bin/ptree ] && exec /usr/bin/ptree "$@"
PATH=/bin:/usr/bin:/usr/sbin:/sbin
export PATH
case $1 in
-*)
echo "
Usage: ptree [ PID | USER ]
Print process tree
PID : extract branch for this process
USER : filter for this (existing) user
USER PID : do both
"
exit
;;
*[!0-9]*)
psopt="-u $1"
shift
;;
*)
psopt="-e"
esac
psopt="$psopt -H -o pid= -o args="
if [ -z "$1" ]; then
ps $psopt
exit
fi
#some effort to add less to the ps list
tmp=/tmp/ptree.$$
trap 'rm -f $tmp' 0 HUP INT TERM
ps $psopt >$tmp
<$tmp awk '
{ ci=index(substr($0,6),$2); o[ci]=$0 }
ci>s[a] { s[++a]=ci }
$1==pid {
for(i=1;i<=a;i++) {
si=s; if(si<=ci) print o[si]
}
walkdown=ci
next
}
ci<=walkdown { exit }
walkdown!=0 { print }
' pid="$1"
Without argument it displays the full process tree, like the pstree command.
A quick exercise: where is my current shell from?
ptree $$
5 Likes
Neo
January 15, 2020, 11:26pm
2
Quick test on macOS
macos$ cat ptree.sh
#!/bin/sh
# Solaris style ptree
[ -x /usr/bin/ptree ] && exec /usr/bin/ptree "$@"
PATH=/bin:/usr/bin:/usr/sbin:/sbin
esac
psopt="$psopt -H -o pid= -o args="
if [ -z "$1" ]; then
ps $psopt
exit
fi
#some effort to add less to the ps list
tmp=/tmp/ptree.$$
trap 'rm -f $tmp' 0 HUP INT TERM
ps $psopt >$tmp
<$tmp awk '
{ ci=index(substr($0,6),$2); o[ci]=$0 }
ci>s[a] { s[++a]=ci }
$1==pid {
for(i=1;i<=a;i++) {
si=s; if(si<=ci) print o[si]
}
walkdown=ci
next
}
ci<=walkdown { exit }
walkdown!=0 { print }
' pid="$1"
macos$ echo $SHELL
/bin/bash
macos$ ./ptree.sh $$
./ptree.sh: line 7: syntax error near unexpected token `esac'
./ptree.sh: line 7: `esac'
macos$
macos$ /bin/sh ./ptree.sh $$
./ptree.sh: line 7: syntax error near unexpected token `esac'
./ptree.sh: line 7: `esac'
2 Likes
Hi
systemd-cgls
Another option
ps xawf -eo pid,user,cgroup,args
2 Likes
Sorry, somehow my copy/paste left out a bunch of lines.
--- Post updated at 11:24 ---
@nezabudka , the goal was to only show a relevant part of the process tree.
1 Like
Neo
January 16, 2020, 4:48am
5
sh-3.2_macos$ ./mig.sh
ps: illegal option -- H
usage: ps [-AaCcEefhjlMmrSTvwXx] [-O fmt | -o fmt] [-G gid[,gid...]]
[-g grp[,grp...]] [-u [uid,uid...]]
[-p pid[,pid...]] [-t tty[,tty...]] [-U user[,user...]]
ps [-L]
sh-3.2$ cat mig.sh
#!/bin/sh
# Solaris style ptree
[ -x /usr/bin/ptree ] && exec /usr/bin/ptree "$@"
PATH=/bin:/usr/bin:/usr/sbin:/sbin
export PATH
case $1 in
-*)
echo "
Usage: ptree [ PID | USER ]
Print process tree
PID : extract branch for this process
USER : filter for this (existing) user
USER PID : do both
"
exit
;;
*[!0-9]*)
psopt="-u $1"
shift
;;
*)
psopt="-e"
esac
psopt="$psopt -H -o pid= -o args="
if [ -z "$1" ]; then
ps $psopt
exit
fi
#some effort to add less to the ps list
tmp=/tmp/ptree.$$
trap 'rm -f $tmp' 0 HUP INT TERM
ps $psopt >$tmp
<$tmp awk '
{ ci=index(substr($0,6),$2); o[ci]=$0 }
ci>s[a] { s[++a]=ci }
$1==pid {
for(i=1;i<=a;i++) {
si=s; if(si<=ci) print o[si]
}
walkdown=ci
next
}
ci<=walkdown { exit }
walkdown!=0 { print }
' pid="$1"
sh-3.2$
macos$ ./mig.sh $$
ps: illegal option -- H
usage: ps [-AaCcEefhjlMmrSTvwXx] [-O fmt | -o fmt] [-G gid[,gid...]]
[-g grp[,grp...]] [-u [uid,uid...]]
[-p pid[,pid...]] [-t tty[,tty...]] [-U user[,user...]]
ps [-L]
macos$ echo $SHELL
/bin/bash
macos$
joker
January 16, 2020, 4:53am
6
I'd like to mention --forest option of ps which I use regularly under linux.
It lacks the here mentioned feature to show only the tree concerning a special pid.
ps ax --forest
...
2406 ? S 0:00 /usr/lib/x86_64-linux-gnu/libexec/kf5/start_kdeinit --kded +kcminit_startup
2411 ? Ss 0:00 kdeinit5: Running...
2413 ? Sl 0:00 \_ /usr/lib/x86_64-linux-gnu/libexec/kf5/klauncher --fd=9
2420 ? Sl 0:01 \_ kded5 [kdeinit5]
2761 ? Sl 0:00 \_ /usr/bin/ksmserver
2791 ? Sl 0:09 | \_ kwin_x11 -session 10dde16a61000157748587300000029330001_1578584288_66599
2799 ? Sl 0:02 | \_ /usr/bin/krunner
2800 ? Sl 0:29 | \_ /usr/bin/plasmashell --shut-up
2801 ? Sl 0:00 | \_ /usr/lib/x86_64-linux-gnu/libexec/polkit-kde-authentication-agent-1
2802 ? Sl 0:00 | \_ /usr/bin/xembedsniproxy
2888 ? Sl 0:00 | \_ /usr/lib/at-spi2-core/at-spi-bus-launcher --launch-immediately
2910 ? S 0:00 | | \_ /usr/bin/dbus-daemon --config-file=/usr/share/defaults/at-spi2/accessibility.conf --nofork --print-address 3
2889 ? Sl 0:00 | \_ /usr/bin/korgac
2856 ? Sl 0:01 \_ /usr/bin/owncloud -session 10dde16a61000157848162200000034850009_1578584288_58686
3486 ? Sl 2:15 \_ /usr/local/bin/firefox
3634 ? Sl 0:41 | \_ /opt/firefox/firefox-61.0.1/firefox-bin -contentproc -childID 3 -isForBrowser -prefsLen 6100 -prefMapSize 258569 -parentBuildID 20200107212822 -greomni /opt/fire
6193 ? Sl 0:18 | \_ /opt/firefox/firefox-61.0.1/firefox-bin -contentproc -childID 20 -isForBrowser -prefsLen 7615 -prefMapSize 258569 -parentBuildID 20200107212822 -greomni /opt/fir
6565 ? Sl 0:04 | \_ /opt/firefox/firefox-61.0.1/firefox-bin -contentproc -childID 25 -isForBrowser -prefsLen 7615 -prefMapSize 258569 -parentBuildID 20200107212822 -greomni /opt/fir
6687 ? Sl 0:00 | \_ /opt/firefox/firefox-61.0.1/firefox-bin -contentproc -childID 26 -isForBrowser -prefsLen 7615 -prefMapSize 258569 -parentBuildID 20200107212822 -greomni /opt/fir
3968 ? Sl 0:08 \_ /usr/bin/konsole
3975 pts/1 Ss 0:00 | \_ /bin/bash
3985 pts/1 S+ 0:00 | | \_ ssh webhost01
5438 pts/2 Ss 0:00 | \_ /bin/bash
5445 pts/2 S+ 0:00 | | \_ ssh webhost01
6922 pts/3 Ss 0:00 | \_ /bin/bash
6984 pts/3 R+ 0:00 | \_ ps ax --forest
4508 ? Sl 0:33 \_ /usr/lib/thunderbird/thunderbird
...
2 Likes
The -H is specific to GNU ps (Linux).
1 Like