用sed命令替换文件中的行

Question

I have this script:

#!/bin/sh
local name="url"
local line='{ "name": "url", "value": "http:\/\/www.example.com\/dir1\/page1" }'

local name2="protocol"
local line2='{ "name": "protocol", "value": "ftp" }'

sed -i "/\<$name2\>/s/.*/$line2/" /mydir/myfile
sed -i "/\<$name\>/s/.*/$line/" /mydir/myfile

myfile contain:

{ "name": "url", "value": "http:\/\/www.example.com\/dir2\/page2" }
{ "name": "url2", "value": "http:\/\/www.example.net/page" }
{ "name": "protocol", "value": "http" }

I detect a problem with / symbol in value field with my sed command. How to fix this error?

Answer 1

Since your files have / all over the place its better to use an alternate regex delimiter ; it is supported by sed.

sed -i "/\<$name2\>/s|.*|$line2|" /mydir/myfile
sed -i "/\<$name\>/s|.*|$line|" /mydir/myfile

Answer 2

Use a different separator like this:

sed -i "/\<$name2\>/s%.*%$line2%" /mydir/myfile

For example, this is a dump I did just now:

printf "eins x eins\nzwei x zwei\nabc x abc\ndef x def\n" | sed "/abc/s%x%y%"

It prints:

eins x eins
zwei x zwei
abc y abc
def x def

As you can see, just the line containing abc gets modified by the s command.

Instead of the % sign you can use any character which does not appear in the value you want to replace . Keep that in mind. You also can use _ or ⌴ or ; or a letter, a number, whatever you like. It just mustn't appear in the value.