RENICE(8) System Manager's Manual RENICE(8)

renice — alter priority of running processes

renice priority [[-gpu] target]

renice -n increment [[-gpu] target]

The renice utility alters the scheduling priority of one or more running processes. The following target parameters are interpreted as process ID's (the default), process group ID's, user ID's or user names. The renice'ing of a process group causes all processes in the process group to have their scheduling priority altered. The renice'ing of a user causes all processes owned by the user to have their scheduling priority altered.

The following options are available:

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.
Interpret target parameters as process group ID's.
Interpret target parameters as process ID's (the default).
Interpret target parameters as user names or user ID's.

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 ID's

Change the priority of process ID's 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 IEEE Std 1003.1-2001 (“POSIX.1”).

The renice utility appeared in 4.0BSD.

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.

October 27, 2020 macOS 15.2