Find and replace any letter within double quotes in a file

Content in test.txt file (test.txt not a ini file type):

abc.display_name="a1 b1 c1"

def.display_name="a2 b2 c2"

​I want to be:

abc.display_name="ok fine"

def.display_name="ok fine"​

I've looked in WordFunc.nsh and TextFunc.nsh but haven't found a solution.

Thank for support.

There is probably a macro out there that can help you, if not, use the plain NSIS file functions to read one line at the time and change the lines you need to and write all of this to a new file that you replace the old file with...