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renice - Unix, Linux Command
- alter priority of running processes
scheduling priority of one or more running processes.
parameters are interpreted as process IDs, process group
IDs, or user names.
a process group causes all processes in the process group
to have their scheduling priority altered.
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
parameters to be interpreted as process group IDs.
parameters to be interpreted as user names.
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
(This prevents overriding administrative fiats.)
may alter the priority of any process
and set the priority to any value in the range
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).
to map user names to user IDs
Non super-users can not increase scheduling priorities of their own processes,
even if they were the ones that decreased the priorities in the first place.
The Linux kernel (at least version 2.0.0) and linux libc (at least
version 5.2.18) does not agree entirely on what the specifics of the
systemcall interface to set nice values is. Thus causes renice to
report bogus previous nice values.
command appeared in
BSD 4.0 .