This lesson will explore the applications that are part of the Linux Ubuntu desktop.

Desktop Applications in Linux Ubuntu

Not all applications have a Graphical User Interface (GUI) or visual component to allow the user to interact via point-and-click. Some applications are designed to be lightweight and accessible only through a command line. This is where we can directly access the Linux shell through text commands, using the Bash language.

The Terminal app is the default command-line interface that comes with Linux desktops (and MacOS). Inside the terminal, we can use commands to navigate the file system, move around files, and write files. In the command line, we can run applications that don't have a visual component at all.

Several small terminal-based utilities provide system information such as the number of processes running, amount of memory currently being used, network configurations, and disk health. Some common examples of useful terminal utility commands on Ubuntu are:
- [fdisk](https://www.man7.org/linux/man-pages/man8/fdisk.8.html) (disk partitions)
- [lsblk](https://man7.org/linux/man-pages/man8/lsblk.8.html) (block device)
- [top](https://man7.org/linux/man-pages/man1/top.1.html) (real-time process monitor)

Server applications also live in the terminal and can be configured there. These applications are the backbone of modern computing. These applications often run continuously in the background to provide a specific service like file sharing. Many of these server applications can often be controlled locally from the terminal or accessed remotely from another computer. Some common examples of server applications that can be found on a typical Ubuntu system are openSSH (secure shell server) and mySQL (database server).

The images shows the terminal running a utility called top. The utility shows real-time CPU usage, memory allocations, free RAM, amount of swap memory used, and actively running commands.

Applications Without an Interface

Along with a browser like Firefox and a word editor like Libre Office, Ubuntu also comes pre-installed with a file manager, a calendar application, and many other useful utilities.

> FUN FACT: Did you know that the development budget for Firefox only equals about one hour of Google revenue?

If we need additional software, it can easily be discovered and installed. Ubuntu offers an "App Store"-like application called Software Center. This allows you to search for and install thousands of applications with a click of a button. Additionally, an experienced user could also manually use the Linux shell via command-line to quickly find and install the same software.

Pre-Installed Applications

Slideshow of some pre-installed Ubuntu desktop apps. The slideshow continuously loops through images of the Gnome file manager, Firefox web browser, Rhythmbox audio player, and LibreOffice document writer applications.

Ubuntu is a popular Linux distribution due to its ease of installation and user-friendliness. This [Debian-based operating system](https://www.debian.org/intro/why_debian) is comprised of lots of free and open-source software. This lesson will focus on the desktop version of Linux Ubuntu. Specifically, we’ll discuss:
- Some open-source applications in Linux and their commercial equivalents
- Pre-Installed applications on the Ubuntu desktop
- Terminal-based applications

The Linux Ubuntu operating system has many similarities to popular commercial-based operating systems like Windows or MacOS. Linux Ubuntu is comprised of a multi-user desktop environment complete with user login, wallpapers, clickable icons, and menus to access applications. Just like in other desktops, we can customize a unique look and feel and manage system inputs and outputs.

We can change screensavers, change our Bluetooth connections, and more! Follow along as we explore this desktop environment, in particular its applications.

Introduction

A quadrant of Ubuntu application images are shown. The upper left corner shows the startup page for the Firefox web browser. The upper right corner shows a blank canvas in the Gimp photo editor. The bottom left corner shows the LibreOffice office suite with an open document, presentation, and spreadsheet. The bottom right corner shows the Gnome file manager.

[Open-source software](https://en.wikipedia.org/wiki/Open_source) is used extensively throughout the Linux operating system. A majority of the applications, utilities, and core components in Linux Ubuntu are open-source.

These open-source applications closely resemble their closed-source/proprietary counterparts often found in Windows or macOS. In fact, Ubuntu comes pre-installed with several useful applications such as:
* a document editor
* an email client
* a music player
* a web browser.

For example, a standard install of Ubuntu will contain an office suite application called LibreOffice. This contains a word processor, spreadsheet, and presentation component that will be very familiar to users of Microsoft Word, Excel, or Powerpoint.

Many other open-source alternatives are available to install on Ubuntu. A few of these are:

| APPLICATION              | FUNCTION / USE                |
| ---------------------------------- | ----------------------------------------- |
| GIMP                            | photo editor                          |
| VLC                               | music/video player/editor |
| Rhythmbox                  | music/podcast player        |
| Thunderbird                 | email client                          |
| Nextcloud/Owncloud | sync client                           |
| Scribus                         | desktop publishing             |
| Inkscape                      | graphics editor                    |

Open-Source and Windows/macOS Equivalents

Congratulations, we’ve reached the end of this lesson! We can see that the Linux Ubuntu desktop is really not that much different from the Windows or macOS desktop that may be more familiar to most. Ubuntu provides similar tools and applications but prioritizes open-source software over closed-source.

To review, we’ve discussed:
- Open-source software in Linux and proprietary software equivalents
- Pre-Installed Ubuntu applications
- Non-graphical or Terminal-based applications

Ubuntu Linux comes pre-installed with a variety of common applications that will get you up and running in no time,As we become more familiar with the Linux environment, we may look for more speed and functionality in non-graphical applications in the command line where we can directly communicate with the Linux shell.

We encourage you to explore these applications in your own Linux desktop environment!

Static view of the Ubuntu desktop and some of its pre-installed applications. The image shows a narrow menu bar of favorite application icons on the left. The center of the image shows icons for all the pre-installed applications, utilities, and settings.