Ubuntu – How to identify a zombie process

Check out Process Explorer. It can arrange processes in a parental hierarchy, so you can see at a glance what process started what.

Plus it has a ton of other useful features (such as inspecting a program's launch parameters- this will also help you identify what is starting python) and can be set to replace the Task Manager.

Add the l option to your ps command line. This is the option for long output. The parent process id is one of the additional columns -- labeled PPID.

$ ps l
F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY        TIME COMMAND
0   508  3344  4498  18   0   2452  1236 wait   Ss   pts/12     0:00 /bin/sh
0   508  4467 17796  15   0   4664  1572 wait   Ss   pts/5      0:00 -/bin/bash
0   508  4498  4467  15   0  23032 15108 -      S+   pts/5      2:20 emacs -nw
0   508  4532 17796  15   0   4532  1464 wait   Ss   pts/13     0:00 -/bin/bash
0   508  4916 17796  15   0   4664  1648 wait   Ss   pts/7      0:01 -/bin/bash

Another option is the pstree command to show an ascii tree representation of the processes. You'll probably want the -p option to show process ids.

$ pstree -p dharris
screen(17796)─┬─bash(4467)───emacs(4498)───sh(3344)───sh(3345)
              ├─bash(4532)───su(31037)───bash(31041)
              ├─bash(4916)───pstree(26456)
              ├─bash(13547)───su(20442)───bash(20443)
              └─bash(17797)

sshd(25813)───bash(25817)───screen(25870)