renice(1M)renice(1M)NAMErenice - alter priority of running processes
SYNOPSIS
newoffset] id ...
DESCRIPTION
The command alters the system nice value (used in the system scheduling
priority) of one or more running processes specified by id .... The
new system nice value is set to 20 + newoffset, and is limited to the
range 0 to 39. However if the environment variable is set, the new
system nice value is set to current nice value + newoffset. Processes
with lower system nice values run at higher system priorities than pro‐
cesses with higher system nice values. The option of the command shows
the current priority and nice value for processes. See also nice(1).
To reduce the system nice value of a process, or to set it to a value
less than 20 (with a negative newoffset), a user must have appropriate
privileges. Otherwise, users cannot decrease the system nice value of
a process and can only increase it within the range 20 to 39, to pre‐
vent overriding any current administrative restrictions.
To alter the system nice value of another user's process, a user must
have appropriate privileges. Otherwise, users can only affect pro‐
cesses that they own.
Options
recognizes the following options. If no or option is specified, the
default is
Interpret each id as a process group ID. All processes in each
process group have their system nice value
altered. Only users with appropriate privileges
can use this option.
Change the system nice value of each affected process to 20 +
newoffset. If the environment variable is set,
the system nice value of each affected process
is changed to current nice value + newoffset.
If newoffset is negative, the system nice value
is set to 20 minus the absolute value of newoff‐
set. If the environment variable is set and the
newoffset is negative, the system nice value is
set to current nice value minus the absolute
value of newoffset. Only users with appropriate
privileges can reduce the system nice value or
set it to less than 20. If this option is omit‐
ted, newoffset defaults to 10.
Interpret each id as a process ID. This is the default.
Note: id is a process ID as reported by the com‐
mand, not a job number (e.g., as used by some
shells.
Interpret each id as a user name or user ID number. All pro‐
cesses owned by each specified user have their
system nice values altered. Only users with
appropriate privileges can use this option for
user names and IDs other than their own.
RETURN VALUES
returns a 0 when successful, and a non-zero value when unsuccessful.
EXTERNAL INFLUENCES
Single-byte character code sets are supported.
DIAGNOSTICS
reports the old and new newoffset values (system nice value − 20) of
the affected processes if the operation requested completes success‐
fully. Otherwise, an error message is displayed to indicate the reason
for failure.
However, if the environment variable is set, no reporting is done
unless the command fails.
EXAMPLES
Use default values to decrease the priority of process The id type
defaults to and newoffset defaults to setting the process to a system
nice value of 30.
Change the system nice value for all processes owned by user and user
to 33 (newoffset=13). (Affecting other users processes requires appro‐
priate privileges.)
Change the system nice value of all processes in process group 20 to
(Lowering the system nice value of a process group requires appropriate
privileges.)
WARNINGS
Users who do not have appropriate privileges cannot reduce the system
nice values of their own processes, even if they increased them in the
first place.
FILES
Maps user names to user
ID's
SEE ALSOnice(1), ps(1), getpriority(2), nice(2).
STANDARDS CONFORMANCErenice(1M)
