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.\" $NetBSD: sysctl.8,v 1.4 1995/09/30 07:12:49 thorpej Exp $
.\"
.\" Copyright (c) 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)sysctl.8 8.1 (Berkeley) 6/6/93
.\"
.Dd "June 6, 1993"
.Dt SYSCTL 8
.Os
.Sh NAME
.Nm sysctl
.Nd get or set kernel state
.Sh SYNOPSIS
.Nm sysctl
.Op Fl n
.Ar name ...
.Nm sysctl
.Op Fl n
.Fl w
.Ar name=value ...
.Nm sysctl
.Op Fl n
.Fl aA
.Sh DESCRIPTION
The
.Nm sysctl
utility retrieves kernel state and allows processes with
appropriate privilege to set kernel state.
The state to be retrieved or set is described using a
``Management Information Base'' (``MIB'') style name,
described as a dotted set of components.
The
.Fl a
flag can be used to list all the currently available string or integer values.
The
.Fl A
flag will list all the known MIB names including tables.
Those with string or integer values will be printed as with the
.Fl a
flag; for the table values,
the name of the utility to retrieve them is given.
.Pp
The
.Fl n
flag specifies that the printing of the field name should be
suppressed and that only its value should be output.
This flag is useful for setting shell variables.
For example, to save the pagesize in variable psize, use:
.Bd -literal -offset indent -compact
set psize=`sysctl -n hw.pagesize`
.Ed
.Pp
If just a MIB style name is given,
the corresponding value is retrieved.
If a value is to be set, the
.Fl w
flag must be specified and the MIB name followed
by an equal sign and the new value to be used.
.Pp
The information available from
.Nm sysctl
consists of integers, strings, and tables.
The tabular information can only be retrieved by special
purpose programs such as
.Nm ps ,
.Nm systat ,
and
.Nm netstat .
The string and integer information is summaried below.
For a detailed description of these variable see
.Xr sysctl 3 .
The changeable column indicates whether a process with appropriate
privilege can change the value.
.Bl -column net.inet.ip.forwardingxxxxxx integerxxx
.It Sy Name Type Changeable
.It kern.ostype string no
.It kern.osrelease string no
.It kern.osrevision integer no
.It kern.version string no
.It kern.maxvnodes integer yes
.It kern.maxproc integer yes
.It kern.maxfiles integer yes
.It kern.maxpartitions integer no
.It kern.rawpartition integer no
.It kern.argmax integer no
.It kern.securelevel integer raise only
.It kern.hostname string yes
.It kern.hostid integer yes
.It kern.clockrate struct no
.It kern.posix1version integer no
.It kern.ngroups integer no
.It kern.job_control integer no
.It kern.saved_ids integer no
.It kern.link_max integer no
.It kern.max_canon integer no
.It kern.max_input integer no
.It kern.name_max integer no
.It kern.path_max integer no
.It kern.pipe_buf integer no
.It kern.chown_restricted integer no
.It kern.no_trunc integer no
.It kern.vdisable integer no
.It kern.boottime struct no
.It vm.loadavg struct no
.It machdep.console_device dev_t no
.It net.inet.ip.forwarding integer yes
.It net.inet.ip.redirect integer yes
.It net.inet.ip.ttl integer yes
.It net.inet.icmp.maskrepl integer yes
.It net.inet.tcp.rfc1323 integer yes
.It net.inet.udp.checksum integer yes
.It hw.machine string no
.It hw.model string no
.It hw.ncpu integer no
.It hw.byteorder integer no
.It hw.physmem integer no
.It hw.usermem integer no
.It hw.pagesize integer no
.It user.cs_path string no
.It user.bc_base_max integer no
.It user.bc_dim_max integer no
.It user.bc_scale_max integer no
.It user.bc_string_max integer no
.It user.coll_weights_max integer no
.It user.expr_nest_max integer no
.It user.line_max integer no
.It user.re_dup_max integer no
.It user.posix2_version integer no
.It user.posix2_c_bind integer no
.It user.posix2_c_dev integer no
.It user.posix2_char_term integer no
.It user.posix2_fort_dev integer no
.It user.posix2_fort_run integer no
.It user.posix2_localedef integer no
.It user.posix2_sw_dev integer no
.It user.posix2_upe integer no
.El
.Sh EXAMPLES
.Pp
For example, to retrieve the maximum number of processes allowed
in the system, one would use the follow request:
.Bd -literal -offset indent -compact
sysctl kern.maxproc
.Ed
.Pp
To set the maximum number of processes allowed
in the system to 1000, one would use the follow request:
.Bd -literal -offset indent -compact
sysctl -w kern.maxproc=1000
.Ed
.Pp
Information about the system clock rate may be obtained with:
.Bd -literal -offset indent -compact
sysctl kern.clockrate
.Ed
.Pp
Information about the load average history may be obtained with
.Bd -literal -offset indent -compact
sysctl vm.loadavg
.Ed
.Sh FILES
.Bl -tag -width <netinet/icmpXvar.h> -compact
.It Pa <sys/sysctl.h>
definitions for top level identifiers, second level kernel and hardware
identifiers, and user level identifiers
.It Pa <sys/socket.h>
definitions for second level network identifiers
.It Pa <sys/gmon.h>
definitions for third level profiling identifiers
.It Pa <vm/vm_param.h>
definitions for second level virtual memory identifiers
.It Pa <netinet/in.h>
definitions for third level Internet identifiers and
fourth level IP identifiers
.It Pa <netinet/icmp_var.h>
definitions for fourth level ICMP identifiers
.It Pa <netinet/udp_var.h>
definitions for fourth level UDP identifiers
.El
.Sh SEE ALSO
.Xr sysctl 3
.Sh HISTORY
.Nm sysctl
first appeared in 4.4BSD.
|
