Thank you, Cristoforo (++) for your excellent explanation.

I wanted to add that for point (2), in addition to escaping the content($_) (with \Q and \E), the line appends the alternation meta-chaacter (|).

This makes the regular expression search for ANY of the lines in the smallfile.
Note also the "chop" statement which deletes the extra "|" appended.

                We're living in a golden age. All you need is gold. -- D.W. Robertson.

In reply to Re^4: searching in large file by NetWallah
in thread searching in large file by sabas

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