NetBSD/usr.sbin/sysctl/sysctl.8

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.\" $NetBSD: sysctl.8,v 1.32 1999/10/14 09:33:52 jdolecek 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)
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.\" 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 proc top-level MIB has a special semantic: it represent per-process values
and as such may differ from one process to another. The second-level name
is the pid of the process (in decimal form), or the special word 'curproc'.
For variables below 'proc.<pid>.rlimit', the integer value may be remplaced
with the string 'unlimited' if it matches the magic value used to disable
a limit.
.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.inet6.tcp6.syn_cache_intervalxxxxxx 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.msgbufsize 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 kern.autonicetime integer yes
.It kern.autoniceval integer yes
.It kern.fsync integer no
.It kern.sysvmsg integer no
.It kern.sysvsem integer no
.It kern.sysvshm integer no
.It kern.defcorename string yes
.It kern.synchronized_io integer no
.It kern.iov_max integer no
.It kern.mbuf.msize integer no
.It kern.mbuf.mclsize integer no
.It kern.mbuf.nmbclusters integer raise only
.It kern.mbuf.mblowat integer yes
.It kern.mbuf.mcllowat integer yes
.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.ip.forwsrcrt integer yes
.It net.inet.ip.directed-broadcast integer yes
.It net.inet.ip.allowsrcrt integer yes
.It net.inet.ip.subnetsarelocal integer yes
.It net.inet.ip.mtudisc integer yes
.It net.inet.ip.anonportmin integer yes
.It net.inet.ip.anonportmax integer yes
.It net.inet.ip.mtudisctimeout integer yes
.It net.inet.icmp.maskrepl integer yes
.It net.inet.tcp.rfc1323 integer yes
.It net.inet.tcp.sendspace integer yes
.It net.inet.tcp.recvspace integer yes
.It net.inet.tcp.mssdflt integer yes
.It net.inet.tcp.syn_cache_limit integer yes
.It net.inet.tcp.syn_bucket_limit integer yes
.It net.inet.tcp.syn_cache_interval integer yes
.It net.inet.tcp.init_win integer yes
.It net.inet.tcp.init_win integer yes
.It net.inet.tcp.mss_ifmtu integer yes
.It net.inet.tcp.sack integer yes
.It net.inet.tcp.win_scale integer yes
.It net.inet.tcp.timestamps integer yes
.It net.inet.tcp.compat_42 integer yes
.It net.inet.tcp.cwm integer yes
.It net.inet.tcp.cwm_burstsize integer yes
.It net.inet.tcp.ack_on_push integer yes
.It net.inet.tcp.keepidle integer yes
.It net.inet.tcp.keepintvl integer yes
.It net.inet.tcp.keepcnt integer yes
.It net.inet.tcp.slowhz integer no
.It net.inet.tcp.log_refused integer yes
.It net.inet.udp.checksum integer yes
.It net.inet.udp.sendspace integer yes
.It net.inet.udp.recvspace integer yes
.It net.inet.ipsec.def_policy integer yes
.It net.inet.ipsec.esp_trans_deflev integer yes
.It net.inet.ipsec.esp_net_deflev integer yes
.It net.inet.ipsec.ah_trans_deflev integer yes
.It net.inet.ipsec.ah_net_deflev integer yes
.It net.inet.ipsec.inbound_call_ike integer yes
.It net.inet.ipsec.ah_cleartos integer yes
.It net.inet.ipsec.ah_offsetmask integer yes
.It net.inet.ipsec.dfbit integer yes
.It net.inet.ipsec.ecn integer yes
.It net.inet6.tcp6.mssdflt integer yes
.It net.inet6.tcp6.do_rfc1323 integer yes
.It net.inet6.tcp6.keepidle integer yes
.It net.inet6.tcp6.keepinterval integer yes
.It net.inet6.tcp6.keepcount integer yes
.It net.inet6.tcp6.maxpersistidle integer yes
.It net.inet6.tcp6.sendspace integer yes
.It net.inet6.tcp6.recvspace integer yes
.It net.inet6.tcp6.conntimeo integer yes
.It net.inet6.tcp6.pmtu integer yes
.It net.inet6.tcp6.pmtu_expire integer yes
.It net.inet6.tcp6.pmtu_probe integer yes
.It net.inet6.tcp6.43maxseg integer yes
.It net.inet6.tcp6.syn_cache_limit integer yes
.It net.inet6.tcp6.syn_bucket_limit integer yes
.It net.inet6.tcp6.syn_cache_interval integer yes
.It net.inet6.udp6.sendmax integer yes
.It net.inet6.udp6.recvspace integer yes
.It net.inet6.ip6.forwarding integer yes
.It net.inet6.ip6.redirect integer yes
.It net.inet6.ip6.hlim integer yes
.It net.inet6.ip6.maxfragpackets integer yes
.It net.inet6.ip6.accept_rtadv integer yes
.It net.inet6.ip6.keepfaith integer yes
.It net.inet6.ip6.log_interval integer yes
.It net.inet6.ip6.hdrnestlimit integer yes
.It net.inet6.ip6.dad_count integer yes
.It net.inet6.ip6.auto_flowlabel integer yes
.It net.inet6.ip6.defmcasthlim integer yes
.It net.inet6.ip6.gif_hlim integer yes
.It net.inet6.ip6.kame_version string no
.It net.inet6.ipsec6.def_policy integer yes
.It net.inet6.ipsec6.esp_trans_deflev integer yes
.It net.inet6.ipsec6.esp_net_deflev integer yes
.It net.inet6.ipsec6.ah_trans_deflev integer yes
.It net.inet6.ipsec6.ah_net_deflev integer yes
.It net.inet6.ipsec6.inbound_call_ike integer yes
.It net.inet6.ipsec6.ecn integer yes
.It net.inet6.icmp6.rediraccept integer yes
.It net.inet6.icmp6.redirtimeout integer yes
.It net.inet6.icmp6.errratelimit integer yes
.It net.inet6.icmp6.nd6_prune integer yes
.It net.inet6.icmp6.nd6_delay integer yes
.It net.inet6.icmp6.nd6_umaxtries integer yes
.It net.inet6.icmp6.nd6_mmaxtries integer yes
.It net.inet6.icmp6.nd6_useloopback integer yes
.It net.inet6.icmp6.nd6_proxyall integer yes
.It net.key.debug integer yes
.It net.key.spi_try integer yes
.It net.key.spi_min_value integer yes
.It net.key.spi_max_value integer yes
.It net.key.random_int integer yes
.It net.key.kill_int integer yes
.It net.key.acq_exp_int integer yes
.It net.key.acq_maxtime 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 hw.machine_arch string 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
.It ddb.radix integer yes
.It ddb.maxoff integer yes
.It ddb.maxwidth integer yes
.It ddb.tabstops integer yes
.It ddb.lines integer yes
.It ddb.onpanic integer yes
.It ddb.fromconsole integer yes
.It proc.<pid>.corename string yes
.It proc.<pid>.rlimit.cputime.soft integer yes
.It proc.<pid>.rlimit.cputime.hard integer yes
.It proc.<pid>.rlimit.filesize.soft integer yes
.It proc.<pid>.rlimit.filesize.hard integer yes
.It proc.<pid>.rlimit.datasize.soft integer yes
.It proc.<pid>.rlimit.datasize.hard integer yes
.It proc.<pid>.rlimit.stacksize.soft integer yes
.It proc.<pid>.rlimit.stacksize.hard integer yes
.It proc.<pid>.rlimit.coredumpsize.soft integer yes
.It proc.<pid>.rlimit.coredumpsize.hard integer yes
.It proc.<pid>.rlimit.memoryuse.soft integer yes
.It proc.<pid>.rlimit.memoryuse.hard integer yes
.It proc.<pid>.rlimit.memorylocked.soft integer yes
.It proc.<pid>.rlimit.memorylocked.hard integer yes
.It proc.<pid>.rlimit.maxproc.soft integer yes
.It proc.<pid>.rlimit.maxproc.hard integer yes
.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
.Pp
To view the values of the per-process variables of the current shell,
the request:
.Bd -literal -offset indent -compact
sysctl proc.$$
.Ed
can be used if the shell interpreter remplaces $$ with it's pid (this is true
for most shells).
.Pp
To redirect core dumps to the /var/tmp/<username> directory,
.Bd -literal -offset indent -compact
sysctl -w proc.$$.corename=/var/tmp/%u/%n.core
.Ed
Shall be used.
.Bd -literal -offset indent -compact
sysctl -w proc.curproc.corename=/var/tmp/%u/%n.core
.Ed
changes the value for the sysctl process itself, and will not have the desired
effect.
.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
.Bx 4.4 .