UNIX for Dummies Questions & Answers

hello everybody:
I have some job running on tru64 system and Im the root, due to limited resources I end up with my job ( vdump) for example taking the lowest share, I researched the nice command on the net, but couldnt get enough info, can I use it to already running process or I only use it while launching the job.
can I use it to add the priority to all certain user's processes or just to one process at a time ??
and what are the best options to use wth that command.

Thanks alot guys.

Use nice when you invoke the command, else use renice if the process is already running.

The man pages for both commands clearly detail options and usage.

Cheers
ZB