UNIX for Dummies Questions & Answers

Hi,

I have a script that calls other scripts/commands which may or may not spawn other process.

From my understanding, when I do a ps -ef, the highest numbered process ID is supposed to be the parent ID of all the other related child processes, is this correct?

In most or all circumstances, I do a ps -ef | grep <processid> of my script and anything that spawns off that process IDs I assumed are the child processes of my script. If I want to terminate my script and all other child processes, then I kill the parent ID which is the highest numbered PID and this will subsequently kill all other child process IDs, is this correct?

Now, my question is whether there is any quick way of showing what are the child processes of a parent ID instead of what am currently doing now which is visually checking which one is the parent ID and "assuming" that the highest numbered PID is the parent ID of all the other processes.

Below is a sample output of running ps -ef | grep exp | grep -v grep. I assume from the output below that the parent process/ID is PID 11322, is that correct?

Any advice or suggestion will be much appreciated. Thanks in advance.

Code:

oracle   11154 11153  0 21:20 ?        00:00:00 /bin/sh -c (. ~oracle/.profile; /bin/ksh /usr/local/oracle/scripts/expdp_o
oracle   11155 11154  0 21:20 ?        00:00:00 /bin/sh -c (. ~oracle/.profile; /bin/ksh /usr/local/oracle/scripts/expdp_o
oracle   11190 11155  0 21:20 ?        00:00:00 /bin/ksh /usr/local/oracle/scripts/expdp_schema.ksh dev01
oracle   11322 11190  0 21:20 ?        00:00:00 expdp

You're incorrect in your reasoning, the output shows a clear inheritance tree. For your own enlightenment try the following

Code:

ps -ef | egrep  '^ *(UID|exp)' | grep -v grep

The first line of the ps -ef output lets you know the contents of the column below each title.

Code:

UID        PID  PPID  C STIME TTY          TIME CMD

PPID is the parent process ID , so you could check for your PID in the 3rd column (assuming GNU or SunOS ps here) and report the second column if true.
The following will return all process spawned by init (PID=1)

Code:

ps -ef | awk '{if ($3 == 1) print $2 ": " $8;}'

No, this is totally wrong.

with your "ps" listing there are two relevant columns:
PID = Process ID of the process
PPID = Process ID of the parent process

It is not unusual for PPID to be less than PID. The simplest example is "init" (PID 1).
Process IDs have a finite maximum number defined in the kernel. On a busy system it is possible for the same PID to be used on the same day. Wise administrators configure the kernel with a large maximum PID.

You don't mention what Operating System you have. Some have the "ptree" command which you may find useful, others have switches to "ps" to generate the tree.

You can also hav a look at

Code:

man ptree

and/or (may depend on your OS)

Code:

man pstree