By default git diff truncates its output to fit into a 80-column terminal.
You can override this by specifying values using the --stat option:
--stat[=<width>[,<name-width>[,<count>]]]
Generate a diffstat. You can override the default output width for
80-column terminal by --stat=<width>. The width of the filename
part can be controlled by giving another width to it separated by a
comma. By giving a third parameter <count>, you can limit the
output to the first <count> lines, followed by ... if there are
more.
These parameters can also be set individually with
--stat-width=<width>, --stat-name-width=<name-width> and
--stat-count=<count>.
For example, by setting the output value to a very large number:
git diff --stat=10000
Note that produces the path relative to the root of the git repository.
(For scripting you might want to use git diff-tree directly since it’s more of a “plumbing” command, although I suspect you’ll be fine either way. Note that you need the same extra text with --stat when using git diff-tree. The essential difference between using the git diff “porcelain” front end, and the git diff-tree plumbing command, is that git diff looks up your configured settings for options like diff.renames to decide whether to do rename detection. Well, that, plus the front end git diff will do the equivalent of git diff-index if you’re comparing a commit with the index, for instance. In other words, git diff reads your config and invokes the right plumbing automatically.)