prog/bash/txt/file2.txt

 1  18  this is
 2  17  an interesting
 3  16  experiment isn't
 4  15  it?
 5  e   2nd field match
 6  13
 7  12
 8  11
 9  f  2nd field match
10   9
11   8
12   7
13   6
14   5
15   4
16   3
17   2
18   1