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renice(1B)

alter priority of running processes

From the original Amiga UNIX 2.1 manual. Some things it mentions may not be in this release.

NAME

renice - alter priority of running processes

SYNOPSIS

/usr/ucb/renice priority pid ...

/usr/ucb/renice priority [ -p pid ...  ] [ -g pgrp ...  ]  [
-u username ...  ]

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. priority is the new priority value.

The following options are available:

-p pid ...  Specify a list of process IDs.

-g pgrp ... Specify  a  list  of  process  group  IDs.   The
            processes  in  the specified process groups have
            their scheduling priority altered.

-u user ... Specify a list of user IDs  or  usernames.   All
            processes owned by each user have their schedul-
            ing altered.

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 20. 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 20. 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).

If only the priority is specified, the current process (alternatively, process group or user) is used.

FILES

/etc/passwd         map user names to user ID's

NOTES

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

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

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.