What you suggest means that you are trying to figure out whether the lines of file 2 are in file 1. Although it is not entirely clear, the OP apparently was trying to know whether the lines of file 1 are in file 2. So, the other way around.

So it's probably the second file that should be loaded into a hash (which is not a problem despite the second file being significantly larger, as it is not that large), and then one should lookup each line of file 1 in the hash.

Update: actually, it is really not clear in which way the OP wants to search: at one point, it says one way, and at another point, it seems to say the other way around.

In reply to Re^2: searching in large file by Laurent_R
in thread searching in large file by sabas

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