RENICE(8) BSD System Managers Manual RENICE(8)
renice - alter priority of running processes
renice priority [[-p] pid ...] [[-g] pgrp ...] [[-u] user ...]
Renice alters the scheduling priority of one or more running processes.
The following who parameters are interpreted as process IDs, process
group IDs, or user names. Reniceing a process group causes all pro
cesses in the process group to have their scheduling priority altered.
Reniceing a user causes all processes owned by the user to have their
scheduling priority altered. By default, the processes to be affected
are specified by their process IDs.
Options supported by renice:
-g Force who parameters to be interpreted as process group IDs.
-u Force the who parameters to be interpreted as user names.
-p Resets the who interpretation to be (the default) process IDs.
renice +1 987 -u daemon root -p 32
would change the priority of process IDs 987 and 32, and all processes
owned by users daemon and root.
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), any
thing negative (to make things go very fast).
/etc/passwd to map user names to user IDs
Non super-users can not increase scheduling priorities of their own pro
cesses, even if they were the ones that decreased the priorities in the
The Linux kernel (at least version 2.0.0) and linux libc (at least ver
sion 5.2.18) does not agree entierly on what the specifics of the system
call interface to set nice values is. Thus causes renice to report bogus
previous nice values.
The renice command appeared in 4.0BSD.
4th Berkeley Distribution June 9, 1993 4th Berkeley Distribution