Question

I have a sample HTML file sitting in git. Recently it needs to be changed completely, so there isn’t much point looking at the diff between the new and the old.

Currently the diff will display like ++-+–+–+—++, and I want it to just display ——–+++++++.

Is there a way to tell git that this file change is a complete change and users does not need to know line differences, but change as a whole?

P.S. the answer showed the way in diff command, but but it would be great if I can specify permanently this for specific file in commit command.

Answer 1

Every commit in git stores a completely new blob for the file, even if the change was a single character change in a text file ( later on it might be packed with just delta etc. )

And you should generally not be worried about how and what git stores ( and disk space is cheap)

Update:

If you are just worried about the diff that you see when a file is rewritten, you can use the -B option with diff:

-B[<n>][/<m>]
–break-rewrites[=[<n>][/<m>]]

Break complete rewrite changes into pairs of delete and create. This
serves two purposes:

It affects the way a change that amounts to a total rewrite of a file
not as a series of deletion and insertion mixed together with a very
few lines that happen to match textually as the context, but as a
single deletion of everything old followed by a single insertion of
everything new, and the number m controls this aspect of the -B option
(defaults to 60%). -B/70% specifies that less than 30% of the original
should remain in the result for git to consider it a total rewrite
(i.e. otherwise the resulting patch will be a series of deletion and
insertion mixed together with context lines).

When used with -M, a totally-rewritten file is also considered as the
source of a rename (usually -M only considers a file that disappeared
as the source of a rename), and the number n controls this aspect of
the -B option (defaults to 50%). -B20% specifies that a change with
addition and deletion compared to 20% or more of the file’s size are
eligible for being picked up as a possible source of a rename to
another file.

There are more complex methods like using filter-branch etc to remove ( and modify) history, but I won’t recommend those in this case.