There was a recent node which addressed a similar problem. See Erase entries from files.

If you use *nix, you could just use comm: 

sort -u FILE1 > FILE1.sorted
sort -u FILE2 > FILE2.sorted 
comm -23 FILE1.sorted FILE2.sorted > FIRST
comm -13 FILE1.sorted FILE2.sorted > SECOND
comm -12 FILE1.sorted FILE2.sorted > common

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In reply to Re: how to find common and not common lines in 2 files? by toolic
in thread how to find common and not common lines in 2 files? by Anonymous Monk

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