I'm not strongly against this, but the thinking was that md5sum itself doesn't need the --zero option when veryifying, whereas other programs could benefit from the simplified processing.

I.e. by disabling --zero working with --check, we restrict checksum files to text format, without restricting any functionality

So the explicit disadvantages of not restricting checksum files to text format are:

• checksum files are no longer textual, and so harder to handle with other tools
• older versions of md5sum can not parse these binary checksum files

• older versions of md5sum can not parse these binary checksum files

Newer versions of md5sum should support checking files generated with --zero. It should have been done when introducing the flag. Anyway the patch is trivial and works.

Closing on the basis of minimizing checksum file format variants