Replace a value of parameter in a file-CodePudding

I have a multiple files named paramaters.txt containing different parameters and their values:

param1 = vaue1
param2 = value2
param3 = value3

And I'd like to replace value of param2 and have

param1 = vaue1
param2 = value4
param3 = value3

I was trying to use sed but I was able to do it if I know the string I want to replace, value2 in my case. But I don't know it (or rather it can be different in different files). I would rather try to find string param2 and replace everything that is on the right side of it. But I don't know how to do it.

Any hint will be appreciated.

CodePudding user response：

An easy way to accomplish what you want is to use sed to find the line with the parameter you want and replace the entire line. Something like this should work:

sed -i 's/^param2 =.*/param2 = value4/' file