How to match one per line in a regex?

Question

I\'m having a problem with a regex I created. My company searches for errors in an error file and tries to match the file to a set of possible strings. If one of the strings

Answer 1

If you check the parameters of re.subn(pattern, repl, string, count=0, flags=0) you see that there is a parameter count, which you can set to 1.