如何通过 sed 或 awk 匹配和替换匹配后的字符串

Question

I have a file which I want to modify into a new file using cat. So the file contains lines like:

name "myName"
place "xyz" 

and so on....

I want these lines to be changed to

name "Jon"
place "paris"

I tried to do it like this but its not working:

cat originalFile | sed 's/^name\*/name "Jon"/' > tempFile 

I tried using all sorts of special characters and it did not work. I am unable to recognize the space characters after name and then "myName".

Answer 1

You may match the rest of the line using .* , and you may match a space with a space, or [[:blank:]] or [[:space:]] :

sed 's/^\(name[[:space:]]\).*/\1"Jon"/;s/^\(place[[:space:]]\).*/\1"paris"/' originalFile > tempFile

Note there are two replace commands here joined with s semicolon. The first parts are wrapped with a capturing group that is necessary because the space POSIX character class is not literal and in order to keep it after replacing the \\1 backreference should be used (to insert the text captured with Group 1).

See the online demo :

s='name "myName"
place "xyz"'
sed 's/^\(name[[:space:]]\).*/\1"Jon"/;s/^\(place[[:space:]]\).*/\1"paris"/' <<< "$s"

Output:

name "Jon"
place "paris"

Answer 2

An awk alternative:

awk '$1=="name"{$0="name \"Jon\""} $1=="place"{$0="place \"paris\""} 1' originalFile

It will work when there're space(s) before name or place .
It's not regex match here but just string compare.
awk separates fields by space characters which including \\n or .

Append > tempFile to it when the results seems correct to you.