Re: Diff: obtain only the different lines of the newest file

[Bob Proulx]

Davide Brini wrote:
> Bob Proulx wrote:
> >   $ comm -13 /tmp/a /tmp/b
> >   four
> >   five
> >   six
> 
> I think this works by accident, since comm needs sorted files.
> I get this:
> 
> $ comm -13 /tmp/a /tmp/b
> four
> comm: file 2 is not in sorted order
> five
> six

Oops!  Yes, you are right.  I had forgotten about that requirement.
My bad.

> Here's an awk solution, assuming the newer file has previously been
> determined (for example with stat as you suggest):
> 
> awk 'NR==FNR{a[$0];next} !($0 in a)' oldfile newfile
> 
> That prints lines in "newfile" that are not in "oldfile".

I like it.

Bob