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.\" from: @(#)renice.8 8.1 (Berkeley) 6/9/93
.\"
.Dd December 6, 2012
.Dt RENICE 8
.Os
.Sh NAME
.Nm renice
.Nd alter priority of running processes
.Sh SYNOPSIS
.Nm
.Ar priority
.Oo
.Op Fl p
.Ar pid ...
.Oc
.Oo
.Fl g
.Ar pgrp ...
.Oc
.Oo
.Fl u
.Ar user ...
.Oc
.Nm
.Fl n
.Ar increment
.Oo
.Op Fl p
.Ar pid ...
.Oc
.Oo
.Fl g
.Ar pgrp ...
.Oc
.Oo
.Fl u
.Ar user ...
.Oc
.Sh DESCRIPTION
.Nm
alters the
scheduling priority of one or more running processes.
The following
.Ar who
parameters are interpreted as process ID's, process group
ID's, or user names.
.Nm Ns 'ing
a process group causes all processes in the process group
to have their scheduling priority altered.
.Nm Ns 'ing
a user causes all processes owned by the user to have
their scheduling priority altered.
By default, the processes to be affected are specified by
their process ID's.
.Pp
Options supported by
.Nm :
.Bl -tag -width Ds
.It Fl g
Force
.Ar who
parameters to be interpreted as process group ID's.
.It Fl n
Instead of changing the specified processes to the given priority,
interpret the following argument as an increment to be applied to
the current priority of each process.
.It Fl u
Force the
.Ar who
parameters to be interpreted as user names.
.It Fl p
Resets the
.Ar who
interpretation to be (the default) process ID's.
.El
.Pp
For example,
.Bd -literal -offset indent
renice +1 987 -u daemon root -p 32
.Ed
.Pp
would change the priority of process ID's 987 and 32, and
all processes owned by users daemon and root.
.Pp
Users other than the super-user may only alter the priority of
processes they own,
and can only monotonically increase their ``nice value''
within the range 0 to
.Dv PRIO_MAX
(20).
(This prevents overriding administrative fiats.)
The super-user
may alter the priority of any process
and set the priority to any value in the range
.Dv PRIO_MIN
(\-20)
to
.Dv PRIO_MAX .
.Pp
Useful priorities are:
0, the ``base'' scheduling priority;
20, the affected processes will run only when nothing at the base priority
wants to;
anything negative, the processes will receive a scheduling preference.
.Sh FILES
.Bl -tag -width /etc/passwd -compact
.It Pa /etc/passwd
to map user names to user ID's
.El
.Sh SEE ALSO
.Xr nice 1 ,
.Xr prenice 1 ,
.Xr getpriority 2 ,
.Xr setpriority 2
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.0 .
.Sh BUGS
Non super-users can not increase scheduling priorities of their own processes,
even if they were the ones that decreased the priorities in the first place.
