What if one string is contained in the other but should not be counted?

That's tricky. Do you really want that? I don't have the time right now to spend the effort on a what-if you won't use.

Do you need to lookahead on both strings?

No, it's optional on the last one. If you had 4 strings, you'd need the lookahead on the first three, but it would be optional on the fourth.

In reply to Re^3: grep for lines containg two variables by ikegami
in thread grep for lines containg two variables by smoss74

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