The --summary option describes newly added, deleted, renamed and
copied files. The --stat option adds diffstat(1) graph to the
output. These options can be combined with other options, such as
-p, and are meant for human consumption.
When showing a change that involves a rename or a copy, --stat
output formats the pathnames compactly by combining common prefix
and suffix of the pathnames. For example, a change that moves
arch/i386/Makefile to arch/x86/Makefile while modifying 4 lines
will be shown like this:
arch/{i386 => x86}/Makefile | 4 +--
The --numstat option gives the diffstat(1) information but is
designed for easier machine consumption. An entry in --numstat
output looks like this:
1 2 README
3 1 arch/{i386 => x86}/Makefile
That is, from left to right:
1. the number of added lines;
2. a tab;
3. the number of deleted lines;
4. a tab;
5. pathname (possibly with rename/copy information);
6. a newline.
When -z output option is in effect, the output is formatted this
way:
1 2 README NUL
3 1 NUL arch/i386/Makefile NUL arch/x86/Makefile NUL
That is:
1. the number of added lines;
2. a tab;
3. the number of deleted lines;
4. a tab;
5. a NUL (only exists if renamed/copied);
6. pathname in preimage;
7. a NUL (only exists if renamed/copied);
8. pathname in postimage (only exists if renamed/copied);
9. a NUL.
The extra NUL before the preimage path in renamed case is to
allow scripts that read the output to tell if the current record
being read is a single-path record or a rename/copy record
without reading ahead. After reading added and deleted lines,
reading up to NUL would yield the pathname, but if that is NUL,
the record will show two paths.
