c:\@Work\Perl\monks\Q.and>perl iter_2_files_1.pl
bad small file line 'SmAlL
' at iter_2_files_1.pl line 107, <$_[...]> line 3.
small file: [["A", "2_1"], ["B", "2_2"]]

A from FILE1 with number 1_1 and A from FILE2 with number 2_1 match
A from FILE1 with number 1_1 and B from FILE2 with number 2_2 DO NOT match
A from FILE1 with number 1_2 and A from FILE2 with number 2_1 match
A from FILE1 with number 1_2 and B from FILE2 with number 2_2 DO NOT match
B from FILE1 with number 1_3 and A from FILE2 with number 2_1 DO NOT match
B from FILE1 with number 1_3 and B from FILE2 with number 2_2 match
bad large file line 'LaRgE
' at iter_2_files_1.pl line 121, <$_[...]> line 4.
C from FILE1 with number 1_4 and A from FILE2 with number 2_1 DO NOT match
C from FILE1 with number 1_4 and B from FILE2 with number 2_2 DO NOT match