1SYSCTL(8)                                                            SYSCTL(8)
2
3
4

NAME

6       sysctl - configure kernel parameters at runtime
7

SYNOPSIS

9       sysctl [-n] [-e] variable ...
10       sysctl [-n] [-e] [-q] -w variable=value ...
11       sysctl [-n] [-e] [-q] -p [filename]...
12       sysctl [-n] [-e] [-q] --system
13       sysctl [-n] [-e] -a
14       sysctl [-n] [-e] -A
15

DESCRIPTION

17       sysctl  is used to modify kernel parameters at runtime.  The parameters
18       available are those listed under /proc/sys/.  Procfs  is  required  for
19       sysctl(8)  support  in  Linux.   You can use sysctl(8) to both read and
20       write sysctl data.
21

PARAMETERS

23       variable
24              The name of a key to read from.  An  example  is  kernel.ostype.
25              The '/' separator is also accepted in place of a '.'.
26
27       variable=value
28              To set a key, use the form variable=value, where variable is the
29              key and value is the value to set it to.  If the value  contains
30              quotes or characters which are parsed by the shell, you may need
31              to enclose the value in double quotes.   This  requires  the  -w
32              parameter to use.
33
34       -n     Use  this option to disable printing of the key name when print‐
35              ing values.
36
37       -e     Use this option to ignore errors about unknown keys.
38
39       -N     Use this option to only print the names. It may be  useful  with
40              shells that have programmable completion.
41
42       -q     Use this option to not display the values set to stdout.
43
44       -w     Use this option when you want to change a sysctl setting.
45
46       -p     Load   in   sysctl   settings  from  the  file(s)  specified  or
47              /etc/sysctl.conf if none given.  Specifying - as filename  means
48              reading data from standard input.
49
50       --system
51              Load  settings  from  all  system configuration files. Files are
52              read from directories in the following list in given order  from
53              top  to  bottom.  Once a file of a given filename is loaded, any
54              file of the same name in subsequent directories is ignored.
55              /run/sysctl.d/*.conf
56              /etc/sysctl.d/*.conf
57              /usr/local/lib/sysctl.d/*.conf
58              /usr/lib/sysctl.d/*.conf
59              /lib/sysctl.d/*.conf
60              /etc/sysctl.conf
61
62       -a     Display all values currently available.
63
64       -A     Same as -a
65

EXAMPLES

67       /sbin/sysctl -a
68
69       /sbin/sysctl -n kernel.hostname
70
71       /sbin/sysctl -w kernel.domainname="example.com"
72
73       /sbin/sysctl -p /etc/sysctl.conf
74

NOTES

76       Please note that modules loaded after sysctl is run  may  override  the
77       settings  (example:  sunrpc.*  settings  are overridden when the sunrpc
78       module is loaded). This may cause some confusion during boot  when  the
79       settings  in sysctl.conf may be overriden. To prevent such a situation,
80       sysctl must be run after the particular module is  loaded  (e.g.,  from
81       /etc/rc.d/rc.local or by using the install directive in modprobe.conf)
82

FILES

84       /proc/sys /etc/sysctl.conf
85

SEE ALSO

87       sysctl.conf(5), modprobe.conf(5)
88

AUTHOR

90       George Staikos, <staikos@0wned.org>
91
92
93
94
95                                  21 Sep 1999                        SYSCTL(8)
Impressum