NAME
renice — alter priority of running processes
SYNOPSIS
renice
[-n
newoffset]
[-g|-p|-u]
id ...
DESCRIPTION
The
renice
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
UNIX95
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 processes with higher system nice values.
The
-l
option of the
ps
command shows the current priority
(PRI)
and nice value
(NI)
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 prevent 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 processes that they own.
Options
renice
recognizes the following options.
If no
-g,
-p,
or
-u
option is specified,
the default is
-p.
- -g id ...
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.
- -n newoffset
Change the system nice value of each affected process to 20 +
newoffset.
If the
UNIX95
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
newoffset.
If the
UNIX95
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 omitted,
newoffset
defaults to 10.
- -p id ...
Interpret each
id
as a process
ID.
This is the default.
Note:
id
is a process
ID
as reported by the
ps
command, not a job number (e.g.,
%1),
as used by some shells.
- -u id ...
Interpret each
id
as a user name or user
ID
number.
All processes 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
renice
returns a 0 when successful, and a non-zero value when unsuccessful.
EXTERNAL INFLUENCES
Single-byte character code sets are supported.
DIAGNOSTICS
renice
reports the old and new
newoffset
values (system nice value - 20)
of the affected processes
if the operation requested completes successfully.
Otherwise, an error message is displayed
to indicate the reason for failure.
However, if the
UNIX95
environment variable is set, no reporting is done unless
the command fails.
EXAMPLES
Use
renice
default values to decrease the priority of process
923.
The
id
type
defaults to
-p,
and
newoffset
defaults to
10,
setting the process to a system nice value of 30.
Change the system nice value for all processes owned by user
john
and user
123
to 33
(newoffset=13).
(Affecting other users processes requires
appropriate privileges.)
Change the system nice value of all processes in process group 20 to
10.
(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
- /etc/passwd
Maps user names to user
ID's
STANDARDS CONFORMANCE
renice: XPG4
Printable version
