doc: clarify that --abbrev=<n> is about the minimum length
Early text written in 2006 explains the "--abbrev=<n>" option to
"show only a partial prefix", without saying that the length of the
partial prefix is not necessarily the number given to the option to
ensure that the output names the object uniquely.
Update documentation for the diff family of commands, "blame",
"branch --verbose", "ls-files" and "ls-tree" to stress that the
short prefix must uniquely refer to an object, and <n> is merely
the mininum number of hexdigits used in the prefix.
Helped-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 573fb9b..706c69b 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -446,7 +446,8 @@
--abbrev[=<n>]::
Instead of showing the full 40-byte hexadecimal object
name in diff-raw format output and diff-tree header
- lines, show only a partial prefix.
+ lines, show the shortest prefix that is at least '<n>'
+ hexdigits long that uniquely refers the object.
In diff-patch output format, `--full-index` takes higher
precedence, i.e. if `--full-index` is specified, full blob
names will be shown regardless of `--abbrev`.
