Customizing Your Shell
======================

Try and choose one shell
------------------------

shell is the main interface for us to interact with the system. There
are various shells, and they are highly customizable. Please try some
of them, and find the best one for you.

====== ========================================
Shell  Description
====== ========================================
bash   default one on most systems
zsh    slightly more sophisticated (recommended)
fish   relatively new one
====== ========================================

.. warning:: You can use `fish <https://pixnio.com/free-images/2017/12/22/2017-12-22-11-06-59.jpg>`_ if you want to but be aware that it uses a
   slightly different syntax from bash and zsh. In the next tutorial, only the
   bash and zsh syntax will be illustrated.

Installation on Ubuntu
----------------------

**bash**:

It should already be installed on your system. But if it is not, you can install it with the following command:

.. code-block:: bash

  $ sudo apt install bash

**zsh**:

.. code-block:: bash

  $ sudo apt install zsh

`A User's Guide to ZSH <http://zsh.sourceforge.net/Guide/>`_

**fish**:

.. code-block:: bash

  $ sudo apt install fish

`Tutorial <https://fishshell.com/docs/current/tutorial.html>`_

Change your default shell
-------------------------

Please use the "chsh" command (change the default shell from bash to zsh)::

  $ chsh
  Password:
  Changing the login shell for student
  Enter the new value, or press ENTER for the default
  	Login Shell [/bin/bash]: /usr/bin/zsh

Then, you need to create a new terminal to see the changes (for example, quit the VM using the command ``exit`` and then log in again with ``ssh``).

Customize your shell
--------------------

There are many customizable factors in shell implementations. We invite you to try it on your own. However, as an example, we explain how to add autocompletion to the **zsh** shell, in this section.

First, you need to install "oh-my-zsh" to manage plugins. For this part, enter the following command in your terminal:

.. code-block:: bash

 $ sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"

Then, you will to download and install two specific plugins which are "zsh-autosuggestions" and "zsh-syntax-highlighting". Enter the following commands:

.. code-block:: bash

 $ git clone https://github.com/zsh-users/zsh-autosuggestions.git $ZSH_CUSTOM/plugins/zsh-autosuggestions
 $ git clone https://github.com/zsh-users/zsh-syntax-highlighting.git $ZSH_CUSTOM/plugins/zsh-syntax-highlighting

Then edit your ".zshrc" configuration file by appending `zsh-autosuggestions & zsh-syntax-highlighting` to `plugins()`:

.. code-block:: bash

 $ nvim ~/.zshrc

For example: ``plugins=(git zsh-autosuggestions zsh-syntax-highlighting)``
 
.. note:: You can find the line by using the ``/^plugins`` command in neovim.

Finally, you need to update your current environment with the following command:

.. code-block:: bash

 $ source ~/.zshrc