Customizing Your Editor
=======================

If you are new to command-line editors, you may feel they are
difficult to use. Indeed, it could be true if you use them without
customization. But, if you customize them for yourself, they can
become your best friend.

Try and choose one editor
-------------------------

There are various editors usable on Linux. There are many others, but these
four are among the most popular. Please try them and find the best one for you.

========== ========================================================
Editor     Description
========== ========================================================
nano       simple, but less customizable.
vim/neovim complex, but highly customizable.
emacs      complex too, but highly customizable.
micro      simple and easier than nano. Mouse cursor is supported.
========== ========================================================

.. note:: neovim is a 2014 fork of vim that enhances the codebase and
   introduces new features.

We recommend *neovim* but it can be a bit difficult to use at first. Read the
small description below to have basic knowledge about it.
*emacs* is also a good choice and is more intuitive than *vim/neovim*.

Getting started on Ubuntu
-------------------------

**nano**:

.. code-block:: bash

  $ sudo apt install nano

`nano Command Manual <https://www.nano-editor.org/dist/v2.2/nano.html>`_

**vim/neovim**:

.. code-block:: bash

  $ sudo apt install neovim # or sudo apt install vim if you prefer the older version

To open a file with neovim, use:

.. code-block:: bash

  $ nvim FILE_NAME

In the following, we will use *vim* to refer to both *vim* and *neovim*, as they
are very similar.

vim has two main "modes": *NORMAL* mode (aka *COMMAND* mode) and *INSERT* mode.
In *NORMAL* mode, pressing keys on your keyboard will execute commands (like
undo ``u``, redo ``r``, find and replace ``:%s/foo/bar/g``, quit ``:q``, etc.).
In *INSERT* mode, you type text. There is a third mode, *VISUAL* mode, that is
used to highlight and edit text in bulk.

To go into *INSERT* mode from *NORMAL* mode, you type ``i``. To go back to
COMMAND mode, you type the ``esc`` key. vim starts out in *NORMAL* mode.

The following commands are useful:

- ``:w`` saves the current changes to a file. If you don't specify a name, changes will be saved to the current file. If you would like to save the file under a different name, specify a filename (``:w file``).
- ``:q`` quits vim. If you have unsaved changes (or cannot quit smoothly for other reasons), you will have an error message.
- ``:q!`` forces vim to quit (without saving changes).
- ``:wq`` saves and quit.

We strongly recommend that you follow the following tutorials:

- `Interactive Vim tutorial <https://www.openvim.com/>`_
- `Vim Adventure <https://vim-adventures.com/>`_

**emacs**:

.. code-block:: bash

  $ sudo apt install emacs

`A guided tour of Emacs <https://www.gnu.org/software/emacs/tour/>`_

**micro**:

.. code-block:: bash

  $ sudo apt install micro

`Tutorial <https://github.com/zyedidia/micro/blob/master/runtime/help/tutorial.md>`_

Customize your editor
---------------------

Please choose an editor and customize it. vim, emacs and micro allow
us to customize appearance. vim and emacs support auto-completion if
properly set up.