Subject: bug#69723: Proposed enhancement

From: John Summerfield <[email-masked]>
Date: Mon, 11 Mar 2024 12:37:22 +0800

I have been using diff to compare directories on two SSDs on my laptop,
tying up two USB ports and immobilising the computer  for about two days.

I've reviewed its options, and don't see a better way of using it.

The man page is a bit short on detail about what it considers
same/different, bu I see that I can choose weather filename case matters,
whether changes in white space matter, whether fit matters when something
has been changed from lower to upper case, etc.

I propose another option, a GNU extension if you like.
--ignore-contents
If filenames are the same, subject to other choices, if the file sizes are
the same, if the *times match, then consider them the same. Essentially,
we're only comparing the file descriptions, not their contents.

I'm ambivalent about dates, perhaps those can be user-choice too, I can
think of a few reasons they might differ. Copy to/from DOS-family
filesystems and NTFS or ext4 etc. Transfer between computers in different
time zones or the transfer program doesn't preserve timestamps.

With this change, instead of running almost two days and finding no
consequential differences, it could have been all over in a couple of
minutes.

Thank you for your time and consideration.

John Summerfield
-- 

Cheers
John