linux命令学习-3-sysctl

sysctl 内核变量配置

Usage:

sysctl [options] [variable[=value] ...]

 

NAME

sysctl - configure kernel parameters at runtime

 

DESCRIPTION

sysctl is used to modify kernel parameters at runtime. The parameters available are those listed under /proc/sys/. Procfs is required for sysctl support

in Linux. You can use sysctl to both read and write sysctl data.

 

Options:

-a, --all display all variables

-A alias of -a

-X alias of -a

--deprecated include deprecated parameters to listing

-b, --binary print value without new line

-e, --ignore ignore unknown variables errors

-N, --names print variable names without values

-n, --values print only values of a variables

-p, --load[=<file>] read values from file

-f alias of -p

--system read values from all system directories

-r, --pattern <expression>

select setting that match expression

-q, --quiet do not echo variable set

-w, --write enable writing a value to variable

-o does nothing

-x does nothing

-d alias of -h

 

-h, --help display this help and exit

-V, --version output version information and exit

  

实例1:

/sbin/sysctl -a

显示所有变量

 

实例2:

只打印固定的一个变量

/sbin/sysctl -n kernel.hostname

 

 

/sbin/sysctl -n net.ipv4.tcp_timestamps

 

 

实例3:

写入内核变量

/sbin/sysctl -w kernel.domainname="example.com"

 

 

实例4:

读取数据

/sbin/sysctl -p/etc/sysctl.conf

无输出

 

实例5:

正则匹配

/sbin/sysctl -a --pattern forward

 

 

/sbin/sysctl -a --pattern forward$

 

 

/sbin/sysctl -a --pattern 'net.ipv4.conf.(eth|wlan)0.arp'