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.\"     from: @(#)renice.8	8.1 (Berkeley) 6/9/93
.\"
.Dd $Mdocdate: May 15 2015 $
.Dt RENICE 8
.Os
.Sh NAME
.Nm renice
.Nd alter priority of running processes
.Sh SYNOPSIS
.Nm renice
.Oo Fl n Oc Ar increment
.Op Fl gpu
.Ar id
.Sh DESCRIPTION
.Nm
alters the scheduling priority of one or more running processes with ID
.Ar id .
Processes may be selected by
process ID,
process group ID,
and
user name or ID.
If none of the
.Fl gpu
options are specified,
the default is to select by process ID.
Multiple processes can be specified in a space separated list.
.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),
which  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
Alter the scheduling priority of all processes in process group
.Ar id .
.It Fl n Ar increment
A positive or negative decimal integer used to modify the
scheduling priority.
For compatibility with historic versions of this utility,
if
.Fl n
is omitted and
.Ar increment
is the first argument to
.Nm ,
then
.Ar increment
is taken as an absolute priority rather than an increment.
.It Fl p
Alter the scheduling priority of process
.Ar id .
.It Fl u
Alter the scheduling priority of all processes belonging to user
.Ar id ,
which may be a user name or ID.
.El
.Sh FILES
.Bl -tag -width /etc/passwd -compact
.It Pa /etc/passwd
for mapping user names to user IDs
.El
.Sh EXIT STATUS
.Ex -std renice
.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 -n +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 -p1003.1-2008
specification,
except the way in which processes are specified differs.
.Pp
The historical behavior of passing
.Ar increment
as an absolute priority is supported for backwards compatibility.
.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.