--abbrev[=<n>]::
Instead of showing the full 40-byte hexadecimal object
name in diff-raw format output and diff-tree header
- lines, show only handful hexdigits prefix. This is
+ lines, show only a partial prefix. This is
independent of --full-index option above, which controls
the diff-patch output format. Non default number of
digits can be specified with --abbrev=<n>.