`git log -1 HEAD` but write `git log -1 HEAD --`; the former will not work
if you happen to have a file called `HEAD` in the work tree.
+ * many commands allow a long option "--option" to be abbreviated
+ only to their unique prefix (e.g. if there is no other option
+ whose name begins with "opt", you may be able to spell "--opt" to
+ invoke the "--option" flag), but you should fully spell them out
+ when writing your scripts; later versions of Git may introduce a
+ new option whose name shares the same prefix, e.g. "--optimize",
+ to make a short prefix that used to be unique no longer unique.
+
ENHANCED OPTION PARSER
----------------------
From the git 1.5.4 series and further, many git commands (not all of them at the
time of the writing though) come with an enhanced option parser.
-Here is an exhaustive list of the facilities provided by this option parser.
+Here is a list of the facilities provided by this option parser.
Magic Options
`git clean -fdx`.
+Abbreviating long options
+~~~~~~~~~~~~~~~~~~~~~~~~~
+Commands that support the enhanced option parser accepts unique
+prefix of a long option as if it is fully spelled out, but use this
+with a caution. For example, `git commit --amen` behaves as if you
+typed `git commit --amend`, but that is true only until a later version
+of Git introduces another option that shares the same prefix,
+e.g `git commit --amenity" option.
+
+
Separating argument from the option
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
You can write the mandatory option parameter to an option as a separate