help with diff

[Simon Matthews]

* A Smith (asmith9983 at gmail.com) [091229 14:40]:
> I'm trying unsuccessfully to use the "--GTYPE-group-format=" option to diff
> to try and extract lines  only in file1, not file2, but I must be
> mis-understanding the syntax as I only get an option error from diff!

Looking at the 'diff' manual:
       LTYPE is `old', `new', or `unchanged'.
              GTYPE is LTYPE or `changed'.

So the option needs to be something like --old-group-format=...

However, based on what you are trying to do, the command 'comm' might be
more appropriate.

Simon