Your examples didn't make this clear... what would you want as output if your two input files were:

  -- FILE 1 --        -- FILE 2 --
Monk apple one       Monk apple one
Punk apple two       Punk peach two
John peach three     John peach two
Jane plum  three     Jack plum  three
[download]

The question is: Which of the following best describes your task?

• The comparison consists of using just the first column as the "key" field, and you just want to print the keys that are unique to one file or the other.
• The comparison involves whole lines -- the first column of a line is printed if the other file does not contain an exact match for the whole line.

If your task is like the first one, you could check out a command line utility script that I posted here. If it's the latter, a different approach would be needed.