How to follow processes and their children with ps

Hi,
I often need to find the child processes of a parent process. There may be a string of 4-5. That is, PPID 884 spawns 890, which spawns 894, which spawns 1017. I'd like to be able to see all of them without having to type in a number of ps -ef commands.

Process groups and session ID's are not helping me. Is there some other switch on ps, or technique, that I'm missing?

Thanks.

You never mentioned which OS you are on.

If you have pstree try this.

pstree -p <pid>

Dangit, I keep forgetting that UNIXA != UNIXB ...even at the man(1) level.

Nice. I see the equivalent in Solaris (which is what I'm on), is ptree. Awesome. Thank you very much!
-mschwage