sysctl is used to modify kernel parameters at runtime. The parameters available
are those listed under /proc/sys/. Procfs is required for
sysctl(8) support in Linux. You can use
sysctl(8) to both read and write sysctl data.
PARAMETERS
Tag
Description
variable
The name of a key to read from. An example is kernel.ostype. The /
separator is also accepted in place of a ..
variable=value
To set a key, use the form variable=value, where variable is the key and
value is the value to set it to. If the value contains quotes or characters
which are parsed by the shell, you may need to enclose the value in double
quotes. This requires the -w parameter to use.
-n
Use this option to disable printing of the key name when printing values.
-e
Use this option to ignore errors about unknown keys.
-N
Use this option to only print the names. It may be useful with shells that
have programmable completion.
-q
Use this option to not display the values set to stdout.
-w
Use this option when you want to change a sysctl setting.
-p
Load in sysctl settings from the file specified or /etc/sysctl.conf if none given.
Specifying - as filename means reading data from standard input.
-a
Display all values currently available. Please see the NOTES.
Avoid using the -a and -A options if possible. Using these options may result in
kernel warnings about using a deprecated sysctl.
Also please note that modules loaded after sysctl is run may override the settings
(example: sunrpc.* settings are overridden when the sunrpc module is loaded). This may
cause some confusion during boot when the settings in sysctl.conf may be
overriden. To prevent such a situation, sysctl must be run after the particular module
is loaded (e.g., from /etc/rc.d/rc.local or by using the install directive in
modprobe.conf)