man/man1/renice.1

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 Portions Copyright (c) 1992, X/Open Company Limited All Rights Reserved
 Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved

 RENICE 1 "Jan 9, 2004"
 NAME
renice - alter priority of running processes
 SYNOPSIS

renice [-n increment] [-i idtype] ID...


renice [-n increment] [-g | -p | -u] ID...


renice priority [-p] pid... [-g gid]... [-p pid]...
 [-u user]...


renice priority -g gid... [-g gid]... [-p pid]...
 [-u user]...


renice priority -u user... [-g gid]... [-p pid]...
 [-u user]...


 DESCRIPTION

The renice command alters the scheduling priority of one or more running
processes. By default, the processes to be affected are specified by their
process IDs.

If the first operand is a number within the valid range of priorities
(-20 to 20), renice will treat it as a priority (as
in all but the first synopsis form). Otherwise, renice will treat it as
an ID (as in the first synopsis form).
 "Altering Process Priority"

Users other than the privileged user may only alter the priority of processes
they own, and can only monotonically increase their "nice value" within the
range 0 to 19. This prevents overriding administrative fiats. The
privileged user may alter the priority of any process and set the priority to
any value in the range -20 to 19. Useful priorities are:
19 (the affected processes will run only when nothing else in the system
wants to); 0 (the "base" scheduling priority),; and any negative value
(to make things go very fast). 20 is an acceptable nice value, but will
be rounded down to 19.
 OPTIONS

renice supports the following option features:


The first operand, priority, must precede the options and can have the
appearance of a multi-digit option.


The -g, -p, and -u options can each take multiple
option-arguments.


The pid option-argument can be used without its -p option.


The -i option can be used to specify the ID type for the ID
list. This is preferred in specifying ID type over the use of the
-g | -p | -u syntax, which is now obsolete. See NOTES.


The following options are supported:
-g

Interprets all operands or just the gid arguments as unsigned decimal
integer process group IDs.


-i

This option, together with the ID list arguments, specifies a class of
processes to which the renice command is to apply. The interpretation of
the ID list depends on the value of idtype. The valid idtype
arguments are: pid, pgid, uid, gid, sid,
taskid, projid, and zoneid.


-n increment

Specifies how the system scheduling priority of the specified process or
processes is to be adjusted. The increment option-argument is a positive
or negative decimal integer that will be used to modify the system scheduling
priority of the specified process or processes. Positive increment values
cause a lower system scheduling priority. Negative increment values may
require appropriate privileges and will cause a higher system scheduling
priority.


-p

Interprets all operands or just the pid arguments as unsigned decimal
integer process IDs. The -p option is the default if no options are
specified.


-u

Interprets all operands or just the user argument as users. If a user
exists with a user name equal to the operand, then the user ID of that
user will be used in further processing. Otherwise, if the operand represents
an unsigned decimal integer, it will be used as the numeric user ID of
the user.


 OPERANDS

The following operands are supported:
ID

A process ID, process group ID, or user name/user ID,
depending on the option selected.


priority

The value specified is taken as the actual system scheduling priority, rather
than as an increment to the existing system scheduling priority. Specifying a
scheduling priority higher than that of the existing process may require
appropriate privileges.


 EXAMPLES

Example 1 Adjusting the scheduling priority of process IDs

Adjust the system scheduling priority so that process IDs 987 and
32 would have a lower scheduling priority:

example% renice -n 5 -p 987 32


Example 2 Adjusting the scheduling priority of group IDs

Adjust the system scheduling priority so that group IDs 324 and
76 would have a higher scheduling priority, if the user has the
appropriate privileges to do so:

example% renice -n -4 -g 324 76


Example 3 Adjusting the scheduling priority of a user ID and user name

Adjust the system scheduling priority so that numeric user ID 8 and user
sas would have a lower scheduling priority:

example% renice -n 4 -u 8 sas


 ENVIRONMENT VARIABLES

See environ(5) for descriptions of the following environment variables
that affect the execution of renice: LANG, LC_ALL,
LC_CTYPE, LC_MESSAGES, and NLSPATH.
 EXIT STATUS

The following exit values are returned:
0

Successful completion.


>0

An error occurred.


 FILES
/etc/passwd

map user names to user IDs


 ATTRIBUTES

See attributes(5) for descriptions of the following attributes:


ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Standard


 SEE ALSO

nice(1), passwd(1), priocntl(1), attributes(5),
environ(5), standards(5)
 NOTES

The renice syntax
renice [-n increment] [-i idtype] ID ...


is preferred over the old syntax
renice [-n increment] [-g | -p| -u] ID ...


which is now obsolete.

If you make the priority very negative, then the process cannot be interrupted.

To regain control you must make the priority greater than 0.

Users other than the privileged user cannot increase scheduling priorities of
their own processes, even if they were the ones that decreased the priorities
in the first place.

The priocntl command subsumes the function of renice.