***************************
Step 2: Update and reboot
***************************

.. contents:: Table of Contents

Updating Software Packages
===========================
.. warning::
    Are you starting with a fresh install using ``Ubuntu 18.04 Server``?

    If not, please log in to your service provider and reinstall your OS
    to remove old projects, incorrect configuration, or errors that might
    exist from broken packages.

A VPS with a default install needs updating to install the latest
version of the packages.

* The first thing we should do update all of the software on the VPS.
  This process is very easy because Linux uses automated commands.
* We will use ``apt`` to install and update packages (applications).
  Apt is a packaging manager used by Unbuntu.

Enter these commands one at a time into the terminal window.

``apt update``
    Tells the OS to check for any updates.

``apt -y upgrade``
    Installs any *application updates* that resulted from ``apt update``.

``apt -y dist-upgrade``
    Installs any *distribution updates*, which are major OS updates.

``apt -y autoremove``
    removes any packages that are no longer needed. Instead of leaving
    unused packages on your system, ``apt`` can remove them.

``-y`` flag
    Informs ``apt`` to perform the action without asking for a user prompt.
    Otherwise, the system prompts the user to enter *y* or *n* to continue.

.. code-block:: bash

    sudo apt update
    sudo apt -y upgrade
    sudo apt -y dist-upgrade
    sudo apt -y autoremove

----

.. note:: A note about ``sudo``. Some commands require an elevated prompt, or root.

    * Many default VPSs come configured with the ``root`` user only.
      These VPSs do not require an elevated prompt unless you choose to
      install a standard user.
    * Other VPSs come with a standard user that is part of the super user
      (sudo) group. For these users, you must prefix each command that
      requires an elevated prompt with ``sudo``. Or, just switch to the
      root user using ``sudo su``.

Rebooting Linux
================
Linux rarely needs to reboot. However, it is easier to have the OS
install system-level packages during the reboot process instead of
installing them manually.

Reboot for system updates to take effect. Wait a minute or so to give
the system a chance to reboot before trying to log back into the VPS.

* ``-r`` flag tells the system to reboot now, and not wait for a set time.

.. code-block:: bash

    sudo reboot -n

You can use the equivalent ``shutdown`` command to specify a reason.
This is helpful in a multi-user system. Don't forget the ``-r`` flag
that tells the system to restart after the shutdown.

.. code-block:: bash

    sudo shutdown -r now 'Kernel upgrade requires reboot'

You can see from this output that ``apt`` is installing a boot loader,
which is system firmware.

.. code-block:: bash
    :linenos:
    :emphasize-lines: 1,21

    root@vps298933:~# apt upgrade
    Reading package lists... Done
    Building dependency tree
    Reading state information... Done
    Calculating upgrade... Done
    The following packages will be upgraded:
          apport certbot libnss-systemd libpam-systemd libseccomp2 libsystemd0 libudev1
          libxcb1 python-certbot-nginx python3-acme python3-apport python3-certbot
          python3-certbot-nginx python3-problem-report snapd systemd systemd-sysv udev
    18 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
    Need to get 19.8 MB of archives.
    After this operation, 75.8 kB of additional disk space will be used.
    Do you want to continue? [Y/n] y

    . . .

    Processing triggers for initramfs-tools (0.130ubuntu3.7) ...
    update-initramfs: Generating /boot/initrd.img-4.15.0-46-generic
    Processing triggers for libc-bin (2.27-3ubuntu1) ...
    root@vps298933:~#
    root@vps298933:~# shutdown -r now

    ----------------------------------------------------------------------------------------------

    Session stopped
        - Press <return> to exit tab
        - Press R to restart session
        - Press S to save terminal output to file

    Server unexpectedly closed network connection