Linux Bash：在特定位置的文件中插入一行
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Bash: Inserting a line in a file at a specific location
提问by dgibbs
I am writing a script that will require me to add lines in a specific part of a config file. For example
我正在编写一个脚本，需要我在配置文件的特定部分添加行。例如
Before:
前：
ServerActors=IpServer.UdpServerUplink MasterServerAddress=unreal.epicgames.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master0.gamespy.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master.mplayer.com MasterServerPort=27900
ServerActors=UWeb.WebServer
After:
后：
ServerActors=IpServer.UdpServerUplink MasterServerAddress=unreal.epicgames.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master0.gamespy.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master.mplayer.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master.qtracker.com MasterServerPort=27900
ServerActors=UWeb.WebServer
As you can see there is a new line added. How can my bash script insert the line? I'm guessing I will need to use sed.
如您所见，添加了一个新行。我的 bash 脚本如何插入该行？我猜我需要使用 sed。
采纳答案by Adrian Frühwirth
If you want to add a line after a specific string match:
如果要在特定字符串匹配后添加一行：
$ awk '/master.mplayer.com/ { print; print "new line"; next }1' foo.input
ServerActors=IpServer.UdpServerUplink MasterServerAddress=unreal.epicgames.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master0.gamespy.com MasterServerPort=27900
ServerActors=IpServer.UdpServerUplink MasterServerAddress=master.mplayer.com MasterServerPort=27900
new line
ServerActors=UWeb.WebServer
回答by MPrazz
You can use something like this:
你可以使用这样的东西：
Note that the command must be entered over multiple lines because sed does not allow coding a newline with "\n" or the Ctrl-V/Ctrl-M key combination like some tools. The backslash says "Ignore my hitting the return key, I'm not done with my command yet".
请注意，该命令必须输入多行，因为 sed 不允许像某些工具一样使用“\n”或 Ctrl-V/Ctrl-M 组合键编码换行符。反斜杠表示“忽略我按回车键，我的命令还没有完成”。
sed -i.bak '4i\
This is the new line\
' filename
This should do the trick (It will insert it between line 3 and 4).
这应该可以解决问题（它将在第 3 行和第 4 行之间插入）。
If you want to put this command itself into a shell script, you have to escape the backslashes so they don't get eaten by bash and fail to get passed to sed. Inside a script, the command becomes:
如果您想将此命令本身放入 shell 脚本中，您必须对反斜杠进行转义，这样它们就不会被 bash 吃掉并且无法传递给 sed。在脚本中，命令变为：
sed -i.bak '4i\
This is the new line\
' filename
回答by Kent
awk 'NR==5{print "new line text"}7' file
回答by rubo77
You can add it with sedin your file filenameafter a certain string patternmatch with:
您可以sed在filename某个字符串pattern匹配后将其添加到您的文件中：
sed '/pattern/a some text here' filename
in your example
在你的例子中
sed '/master.mplayer.com/a \ new line' filename
(The backslash masks the first space in the new line, so you can add more spaces at the start)
（反斜杠掩盖了新行中的第一个空格，因此您可以在开头添加更多空格）
