|-g||Force who parameters to be interpreted as process group IDs.|
|-n||Instead of changing the specified processes to the given priority, interpret the following argument as an increment to be applied to the current priority of each process.|
|-u||Force the who parameters to be interpreted as user names or user IDs.|
|-p||Reset the who interpretation to be (the default) process IDs.|
Users other than the super-user may only alter the priority of processes they own, and can only monotonically increase their nice value within the range 0 to PRIO_MAX (20). (This prevents overriding administrative fiats.) The super-user may alter the priority of any process and set the priority to any value in the range PRIO_MIN (-20) to PRIO_MAX. Useful priorities are: 20 (the affected processes will run only when nothing else in the system wants to), 0 (the base scheduling priority), anything negative (to make things go very fast).
/etc/passwd to map user names to user IDs
Change the priority of process IDs 987 and 32, and all processes owned by users daemon and root.
renice +1 987 -u daemon root -p 32
nice(1), rtprio(1), getpriority(2), setpriority(2)
The renice utility conforms to -p1003.1-2001.
The renice utility appeared in BSD 4.0 .
Non super-users cannot increase scheduling priorities of their own processes, even if they were the ones that decreased the priorities in the first place.