Regex positive look behind for regex reverse matching?

Question

How can I match a string literal then reverse direction then match another string literal above it?

Basically match "match" then look behind and match "here:" then match from "here:" to end of string (to eventually delete)

-- input --

Keep this

here:
match test test

this should be deleted

-- expected output (after match and delete) --

   Keep this

DEMO

Answer 1

You don't need to make this movement, you only need to find "here:" and to ensure that the string contains "match" after (if it is not the case, the pattern will fail):

(?s)here:.*?match.*

(?s) the dot can match newlines

However, if it is possible, you will probably obtain better performances using indexOf method with "match" and "here:", comparing the result and cuting the string at the index of "here:"