Re: patch to diff manpage - clarify "-x"

[Stepan Kasal]

Hello Paul,

On Wed, Oct 23, 2002 at 11:45:14PM -0700, Paul Eggert wrote:
> On further thought, I'm not sure that it's necessary to mention
> directories at all in this context.  [...]

>   -r  --recursive  Recursively compare any subdirectories found.
>   -N  --new-file  Treat absent files as empty.
>   --unidirectional-new-file  Treat absent first files as empty.
>   -s  --report-identical-files  Report when two files are the same.
>   -x PAT  --exclude=PAT  Exclude files that match PAT.
>   -X FILE  --exclude-from=FILE  Exclude files that match any pattern in FILE.
>   -S FILE  --starting-file=FILE  Start with FILE when comparing directories.
>   --from-file=FILE1  Compare FILE1 to all operands.  FILE1 can be a directory.
>   --to-file=FILE2  Compare all operands to FILE2.  FILE2 can be a directory.

>From that perspective, -s can be used also when comparing two regular files,
so I'd put it somewhere else, probably next to -q.

--from-file and --to-file can also perfectly be used with regular files.
I'd let them alone in a new section.  That section could perhaps be near
the top, before -c and -u.

All remaining options make sense only when comparing directories.

I guess that the confusion came from this:
 
diff -s file file               # works
diff -x '*_x' file_x file2_x    # doesn't
diff -x '*_x' file_x file_y     # doesn't

Even if the later two sound strange, one might expect it to exit with 0
(no comparison was done).

And what about this:

diff --from-file=file0 file[1-9]* -x file12

If there are files "file0", "file1", ... "file23", one could expect the
above to perform 22 comparisons, omitting "diff file0 file12".

Just some ideas, I agree these corners are not too important.

Have a nice day,
        Stepan