如何在Linux中从命令行替换文件中的此文本？

Question

I have a proxy config file which has the following line:

Allow 212.21.3.44

I'd like to replace that IP address portion with my new IP address when it changes. It would probably be easier to just use the line number when searching for it &ndash I don't think that config file will change at all other than that particular setting.

How can I do it from the command line with something like like Perl, sed, etc.?

Answer 1

如果要使用sed更改特定的行号，可以使用：

sed -i '<line number> s/Allow .*$/Allow <new ip>/g' <filename>

Answer 2

sed -i 's/[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}/my.new.ip.here/' file.txt

-i标志将在适当的位置更改文件（取决于您的发行版/ * nix的风格 - 适用于我的Ubuntu）。

Answer 3

如果行号确实改变了

sed -i '/Allow/s/Allow .*$/Allow <new ip>/' <filename>