+Some options have arguments, some even have default arguments. In that
+case the argument for such option must be spelled in a sticky way:
+``-Oarg``, never ``-O arg`` because for an option that has a default
+argument the latter means "use default value for option ``-O`` and
+pass ``arg`` further to the option parser". For example, ``git grep``
+has an option ``-O`` that passes found files to a program; default
+program for ``-O`` is pager (usually ``less``), but you can use your
+editor::
+
+ $ git grep -Ovim # but not -O vim
+
+BTW, there is a difference between running ``git grep -O`` and ``git
+grep -Oless`` - in the latter case ``git grep`` passes ``+/pattern``
+option to less.
+
+bash/zsh completion
+-------------------
+
+It's a bit hard to type ``git rebase --interactive --preserve-merges
+HEAD~5`` manually even for those who are happy to use command-line,
+and this is where shell completion is of great help. Bash/zsh come
+with programmable completion, often automatically preinstalled and
+enabled, so if you have bash/zsh and git installed, chances are you
+are already done - just go and use it at the command-line.
+
+If you don't have necessary bits preinstalled, install and enable
+bash_completion package. If you want to upgrade your git completion to
+the latest and greatest download necessary file from `git contrib
+<https://git.kernel.org/cgit/git/git.git/tree/contrib/completion>`_.
+
+Git-for-windows comes with git-bash for which bash completion is
+installed and enabled.
+
+bash/zsh prompt
+---------------
+
+For command-line lovers shell prompt can carry a lot of useful
+information. To include git information in the prompt use
+`git-prompt.sh
+<https://git.kernel.org/cgit/git/git.git/tree/contrib/completion/git-prompt.sh>`_.
+Read the detailed instructions in the file.
+
+Search the Net for "git prompt" to find other prompt variants.