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.\"     @(#)renice.8	8.1 (Berkeley) 6/9/93
.\" $FreeBSD$
.\"
.Dd June 9, 1993
.Dt RENICE 8
.Os
.Sh NAME
.Nm renice
.Nd alter priority of running processes
.Sh SYNOPSIS
.Nm
.Ar priority
.Op Oo Fl p Oc Ar pid ...
.Op Oo Fl g Oc Ar pgrp ...
.Op Oo Fl u Oc Ar user ...
.Nm
.Fl n Ar increment
.Op Oo Fl p Oc Ar pid ...
.Op Oo Fl g Oc Ar pgrp ...
.Op Oo Fl u Oc Ar user ...
.Sh DESCRIPTION
The
.Nm
utility 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, user ID's or user names.
The
.Nm Ns 'ing
of a process group causes all processes in the process group
to have their scheduling priority altered.
The
.Nm Ns 'ing
of 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
The following options are available:
.Bl -tag -width indent
.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 or user ID's.
.It Fl p
Reset the
.Ar who
interpretation to be (the default) process ID's.
.El
.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 .
Useful priorities are:
20 (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).
.Sh FILES
.Bl -tag -width /etc/passwd -compact
.It Pa /etc/passwd
to map user names to user ID's
.El
.Sh EXAMPLES
Change the priority of process ID's 987 and 32, and
all processes owned by users daemon and root.
.Pp
.Dl "renice +1 987 -u daemon root -p 32"
.Sh SEE ALSO
.Xr nice 1 ,
.Xr rtprio 1 ,
.Xr getpriority 2 ,
.Xr setpriority 2
.Sh STANDARDS
The
.Nm
utility conforms to
.St -p1003.1-2001 .
.Sh HISTORY
The
.Nm
utility appeared in
.Bx 4.0 .
.Sh BUGS
Non super-users cannot increase scheduling priorities of their own processes,
even if they were the ones that decreased the priorities in the first place.