renice - alter priority of running processes
renice alters the scheduling priority of one or more
running processes. The first argument is the
priority value to
be used. The other arguments are interpreted as process IDs (by
default), process group IDs, user IDs, or user names.
renice'ing a process group causes all processes in the
process group to have their scheduling priority altered.
renice'ing a user causes all processes owned by the
user to have their scheduling priority altered.
Specify the scheduling
priorityto be used for the process, process group, or user. Use of the option -n or --priority is optional, but when used it must be the first argument.
Interpret the succeeding arguments as process group IDs.
Interpret the succeeding arguments as process IDs (the default).
Interpret the succeeding arguments as usernames or UIDs.
Display version information and exit.
Display help text and exit.
to map user names to user IDs
Users other than the superuser may only alter the priority of
processes they own. Furthermore, an unprivileged user can only
increase the "nice value" (i.e., choose a lower priority) and
such changes are irreversible unless (since Linux 2.6.12) the user has a
suitable "nice" resource limit (see ulimit(1p) and
The superuser 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), anything negative (to make things go very fast).
The renice command appeared in 4.0BSD.
The following command would change the priority of the processes with PIDs 987 and 32, plus all processes owned by the users daemon and root:
renice +1 987 -u daemon root -p 32