RENICE(8) BSD System Manager's 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 ID's, process
group ID's, or user names. Renice'ing a process group causes all pro-
cesses in the process group to have their scheduling priority altered.
Renice'ing 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 ID's.
Options supported by renice:
-g Force who parameters to be interpreted as process group ID's.
-u Force the who parameters to be interpreted as user names.
-p Resets the who interpretation to be (the default) process ID's.
renice +1 987 -u daemon root -p 32
would change the priority of process ID's 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 ID's
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 entirely 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