[英]Modify config files with sed in bash
I am trying to set net.ipv4.ip_forward
to 1 in /etc/sysctl.conf
.The following works fine but it sure missing some edge cases 我试图在/etc/sysctl.conf
中将net.ipv4.ip_forward
设置为1.以下工作正常,但确实缺少一些边缘情况
#Enable IP packet forwarding so that our VPN traffic can pass through.
sed -i 's/net.ipv4.ip_forward = 0/net.ipv4.ip_forward = 1/g' /etc/sysctl.conf
sed -i 's/#net.ipv4.ip_forward = 1/net.ipv4.ip_forward = 1/g' /etc/sysctl.conf
grep -qF "net.ipv4.ip_forward" /etc/sysctl.conf || echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
For eg if the sysctl.conf contain any one of the following it won't match 例如,如果sysctl.conf包含以下任何一个,则它将不匹配
#net.ipv4.ip_forward=1
##net.ipv4.ip_forward=1
. ##net.ipv4.ip_forward=1
。
Is there a more reliable way to modify settings in config files ? 是否有更可靠的方法来修改配置文件中的设置?
You can use the -r
switch to enable Extended Regular Expressions( ERE
) in GNU sed
and optionally match the white-space and the #
occurence with the regex ?
您可以使用-r
开关来启用扩展正则表达式( ERE
)在GNU sed
和可选匹配空白和#
occurence用正则表达式?
optional item anchor , 可选项锚 ,
sed -ir 's/#{1,}?net.ipv4.ip_forward ?= ?(0|1)/net.ipv4.ip_forward = 1/g' /etc/sysctl.conf
This will match for any of the below input lines and modify it with the replacement part net.ipv4.ip_forward = 1
这将匹配以下任何输入行,并使用替换部件net.ipv4.ip_forward = 1
修改
net.ipv4.ip_forward=0
net.ipv4.ip_forward = 0
#net.ipv4.ip_forward=0
##net.ipv4.ip_forward = 0
#net.ipv4.ip_forward=1
##net.ipv4.ip_forward=1
#net.ipv4.ip_forward = 1
##net.ipv4.ip_forward = 1
See the RegEx Demo for more clarity. 有关更清晰的信息,请参阅RegEx演示 。
What about removing all lines matching net.ipv4.ip_forward
, no matter whether commented out or not and then appending what you need? 删除匹配net.ipv4.ip_forward
所有行,无论是否注释掉,然后附加你需要的内容怎么样?
fgrep -v net.ipv4.ip_forward /etc/sysctl.conf > /etc/sysctl.conf.tmp
echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf.tmp
mv /etc/sysctl.conf.tmp /etc/sysctl.conf
This is simple and readable. 这很简单易读。
You can use this setting to do it for zero or more spaces and zero or multiple #(comment) 您可以使用此设置为零个或多个空格以及零个或多个#(注释)执行此操作
sed -i 's/[#| ]*net.ipv4.ip_forward[ ]*=[ ]*0/net.ipv4.ip_forward = 1/g' /etc/sysctl.conf
grep -qF "net.ipv4.ip_forward" /etc/sysctl.conf || echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
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