It shouldn't be a surprise since you changed the file format after I posted my reply. You initially said File2.txt looked like 
12345
ABCDEFANABCDEFGHIJKLMNOPQRSTVVWXWZ
67890
ABACFHAYJAYAFANJAKALAHUSSGSJISUSSKSOWUWSLSS

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In reply to Re^3: Regex problem by ikegami
in thread Regex problem by ashnator

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