159 lines
3.9 KiB
Groff
159 lines
3.9 KiB
Groff
.\" Copyright 1999, George Staikos (staikos@0wned.org)
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.\" This file may be used subject to the terms and conditions of the
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.\" GNU General Public License Version 2, or any later version
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.\" at your option, as published by the Free Software Foundation.
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.\" This program is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details."
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.TH SYSCTL "8" "Jan 2012" "procps-ng" "System Administration"
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.SH NAME
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sysctl \- configure kernel parameters at runtime
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.SH SYNOPSIS
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.B sysctl
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[\fIoptions\fR] [\fIvariable\fR[\fI=value\fR]] [...]
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.SH DESCRIPTION
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.B sysctl
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is used to modify kernel parameters at runtime. The parameters available
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are those listed under /proc/sys/. Procfs is required for
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.B sysctl
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support in Linux. You can use
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.B sysctl
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to both read and write sysctl data.
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.SH PARAMETERS
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.TP
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.I variable
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The name of a key to read from. An example is kernel.ostype. The '/'
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separator is also accepted in place of a '.'.
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.TP
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.IR variable = value
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To set a key, use the form
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.IR variable = value
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where
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.I variable
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is the key and
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.I value
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is the value to set it to. If the value contains quotes or characters
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which are parsed by the shell, you may need to enclose the value in double
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quotes. This requires the
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.B \-w
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parameter to use.
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.TP
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\fB\-n\fR, \fB\-\-values\fR
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Use this option to disable printing of the key name when printing values.
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.TP
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\fB\-e\fR, \fB\-\-ignore\fR
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Use this option to ignore errors about unknown keys.
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.TP
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\fB\-N\fR, \fB\-\-names\fR
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Use this option to only print the names. It may be useful with shells that
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have programmable completion.
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.TP
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\fB\-q\fR, \fB\-\-quiet\fR
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Use this option to not display the values set to stdout.
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.TP
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\fB\-w\fR, \fB\-\-write\fR
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Use this option when you want to change a sysctl setting.
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.TP
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\fB\-p\fR[\fIFILE\fR], \fB\-\-load\fR[=\fIFILE\fR]
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Load in sysctl settings from the file specified or /etc/sysctl.conf if none
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given. Specifying \- as filename means reading data from standard input.
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.TP
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\fB\-a\fR, \fB\-\-all\fR
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Display all values currently available.
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.TP
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\fB\-\-deprecated\fR
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Include deprecated parameters to
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.B \-\-all
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values listing.
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.TP
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\fB\-b\fR, \fB\-\-binary\fR
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Print value without new line.
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.TP
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\fB\-\-system\fR
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Load settings from all system configuration files.
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.br
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/run/sysctl.d/*.conf
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.br
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/etc/sysctl.d/*.conf
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.br
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/usr/local/lib/sysctl.d/*.conf
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.br
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/usr/lib/sysctl.d/*.conf
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.br
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/lib/sysctl.d/*.conf
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.br
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/etc/sysctl.conf
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.TP
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\fB\-\-pattern\fR \fIpattern\fR
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Only apply settings that match
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.IR pattern .
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The
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.I pattern
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uses extended regular expression syntax.
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.TP
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\fB\-A\fR
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Alias of \fB\-a\fR
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.TP
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\fB\-d\fR
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Alias of \fB\-h\fR
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.TP
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\fB\-f\fR
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Alias of \fB\-p\fR
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.TP
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\fB\-X\fR
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Alias of \fB\-a\fR
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.TP
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\fB\-o\fR
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Does nothing in favour of BSD compatibility.
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.TP
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\fB\-x\fR
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Does nothing in favour of BSD compatibility.
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.TP
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\fB\-h\fR, \fB\-\-help\fR
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Display help text and exit.
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.TP
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\fB\-V\fR, \fB\-\-version\fR
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Display version information and exit.
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.SH EXAMPLES
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/sbin/sysctl \-a
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.br
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/sbin/sysctl \-n kernel.hostname
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.br
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/sbin/sysctl \-w kernel.domainname="example.com"
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.br
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/sbin/sysctl \-p/etc/sysctl.conf
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.br
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/sbin/sysctl \-a \-\-pattern forward
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.br
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/sbin/sysctl \-a \-\-pattern forward$
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.br
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/sbin/sysctl \-a \-\-pattern 'net.ipv4.conf.(eth|wlan)0.arp'
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.br
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/sbin/sysctl \-\-system \-\-pattern '^net.ipv6'
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.SH DEPRECATED PARAMETERS
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The
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.B base_reachable_time
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and
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.B retrans_time
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are deprecated. The sysctl command does not allow changing values of there
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parameters. Users who insist to use deprecated kernel interfaces should values
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to /proc file system by other means. For example:
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.PP
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echo 256 > /proc/sys/net/ipv6/neigh/eth0/base_reachable_time
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.SH FILES
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.I /proc/sys
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.br
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.I /etc/sysctl.conf
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.SH SEE ALSO
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.BR sysctl.conf (5)
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.BR regex (7)
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.SH AUTHOR
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.UR staikos\@0wned.org
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George Staikos
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.UE
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.SH "REPORTING BUGS"
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Please send bug reports to
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.UR procps\@freelists.org
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.UE
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