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.\"     from: @(#)renice.8	8.1 (Berkeley) 6/9/93
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt RENICE 8
.Os
.Sh NAME
.Nm renice
.Nd alter priority of running processes
.Sh SYNOPSIS
.Nm renice
.Ar priority
.Oo
.Op Fl g
.Ar pgrp ...
.Oc
.Oo
.Op Fl p
.Ar pid ...
.Oc
.Oo
.Op Fl u
.Ar user ...
.Oc
.Sh DESCRIPTION
.Nm
alters the scheduling
.Em priority
of one or more running processes.
Processes may be selected using the parameters
.Ar pid
(process ID),
.Ar pgrp
(process group ID),
and
.Ar user
(user name).
If no flag is specified,
the default is to select by process ID.
.Pp
Users other than the superuser may only alter the priority of
processes they own,
and can only monotonically increase their
.Dq nice value
within the range 0 to
.Dv PRIO_MAX
(20).
(This prevents overriding administrative fiats.)
The superuser
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:
20 (the affected processes will run only when nothing else
in the system wants to),
0 (the
.Dq base
scheduling priority),
anything negative (to make things go very fast).
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl g Ar pgrp
Alter the scheduling priority of all processes in process group
.Ar pgrp .
.It Fl p Ar pid
Alter the scheduling priority of process
.Ar pid .
.It Fl u Ar user
Alter the scheduling priority of all processes belonging to user
.Ar user .
.El
.Sh FILES
.Bl -tag -width /etc/passwd -compact
.It Pa /etc/passwd
for mapping user names to user IDs
.El
.Sh EXAMPLES
The following example
changes the priority of process IDs 987 and 32,
and all processes owned by users daemon and root:
.Bd -literal -offset indent
# renice +1 987 -u daemon root -p 32
.Ed
.Sh SEE ALSO
.Xr nice 1 ,
.Xr getpriority 2 ,
.Xr setpriority 2
.Sh STANDARDS
The
.Nm
utility is compliant with the
.St -p1003.1-2004
specification,
but its presence is optional.
.Pp
The arguments to flags
.Op Fl gpu
are extensions to that specification.
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.0 .
.Sh BUGS
Non-superusers cannot increase scheduling priorities of their own processes,
even if they were the ones that decreased the priorities in the first place.