Open Source: What It Is and How to Contribute

The English word terminal means to be situated at the end of something, and the term’s meaning in computing has evolved since it was originally coined in the 1960s.

Prior to the development of the first programmable electronic computers, computers were people (mostly women) who used mechanical calculators to compute complex mathematical computations quickly and accurately. The earliest electronic computers, such as Colossus and ENIAC, required specialized technical knowledge and skill to program because programming these machines was a complex process that involved physically entering commands flipping switches, pushing buttons, and manually moving patch cords.

The development of the terminal interface in the 1960s marked a significant shift in the way users interacted with computers because the terminal provided a convenient and much more accessible way to provide input and obtain output, allowing users to remotely interact with a computer via a keyboard and screen. Back when the terminal was first used in computing, what we refer to as the terminal today was the only interface available to the user, while now it is used to refer to a specific type of text-based programming interface. In particular, today a terminal simply refers to a text-based interface that allows a user to interact with a computer by entering commands and receiving output on a display screen.

The English word console comes from the related verb, to console, which means to provide support. In computing, the original meaning of the console was as a physical device that supported input into and output from a computer. The term is still used that way, but it has also come to be synonymous with terminal in some environments. For example, if you search for console on a Windows machine, you may find the terminal program and/or you may find a security console program.

A CLI refers to any interface that works with text-based commands and text-based output. We will be using a shell, which is an example of a CLI.

A shell is a program which parses and interprets the commands you enter in the terminal and then executes them, often using functionality provided directly by the operating system. In other words, a shell is a CLI which serves as the interface between the end-user and the operating system. It is called a shell because it is a user interface layer directly surrounding the kernel, which is the innermost part of the operating system.

The speed one can type a command is typically many times faster than the speed at which one can select a command from a menu.

The shell facilitates features that are unavailable or difficult to access in a GUI. The mouse only allows for picking among the small set of predetermined options from the screen. However, for most systems many more options are actually available.

If you need to do something that is repetitive or requires combining multiple commands, the shell facilitates this too since shells can be programmed using a scripting language, allowing repetitive and/or complex tasks to be automated via a script.

If you are on a Mac, you have a couple of good options. With any Mac, the built-in Terminal program allows you to access a shell. If you are looking for a more customizable and feature-rich terminal program, then you might want to consider iTerm2¹. Opening the Terminal on a Mac works like opening any other program: you can find it in the Applications folder, you can search for it, you can use the Launchpad, or you can use its shortcut which is command(⌘)+T.

On a machine running Linux, the terminal is often also called the Terminal, although depending upon the Linux environment, the name may differ. Konsole may also be used. Regardless of what it is called, you can typically access the terminal in several ways: search for the keyword Terminal, right-click on your desktop and then select "Open Terminal", or use the shortcut Ctrl+Alt+T.

If you are on a Windows machine, you are in good company. In 2023, Windows is by far the most popular OS for desktops and laptopsHowever, if you are on a Windows machine, you will need to do some work to set up a development environment. If you are on a Windows machine, you have a number of options, but assuming everything will be just fine working in your normal Windows environment is simply not going to work. Seriously! So, please save yourself a lot of time, read on, and follow the directions below.

Here is why your normal environment won’t work. In Windows, the terminal/shell is historically called the command prompt (cmd), although a newer very different terminal/shell called PowerShell has also been around for decades. Neither of these terminals/shells are compatible with the default shell programs available on macOS and Linux. Note that for OSS development, it will be vastly superior to have access to a shell that is compatible with the macOS and Linux ones because these are the typical shells that developers use.

If you are running Windows 10 or Windows 11, then it is best to follow the directions from Microsoft on Installing Ubuntu Linux on Windows with WSL2² will give you the best experience by far. Note that you may first need to update your version of Windows, see https://bit.ly/Windows-Update-FAQ. WSL2 provides a full Linux kernel that is integrated into the Windows operating system. After you have followed the linked directions to install WSL2, including the installation of Linux (the default, Ubuntu an excellent choice), be sure to set-up your Linux user information that you will never forget! Once all this is complete, the shell is most easily accessed by searching for Ubuntu in the search tool next to the Windows Icon and selecting it when you see it. For convenience, consider right-clicking on the Ubuntu icon and pinning it to your Start menu or to your Taskbar. Now Ubuntu will provide you a great shell to work with as you are developing, so be sure to use it for all of your development work.

If you are running an earlier version of Windows, or an outdated version of Windows 10 that you cannot update, then you have several choices. For simpler development environments, using MinGW³ provides a lightweight solution, so you might try this. For a more complicated development environment such as one that utilizes virtualization, using a Virtual Machine (VM) environment such as Virtual Box⁴ and installing and running Ubuntu inside the VM is advisable. For a cloud option, see below.

Although Linux, Mac, and Windows (to a lesser extent) are by far the most typical OSs, developing in another OS environment might also be possible. For example, searching the Internet on "software development in ChromeOS" will provide several useful links for how to set up a development environment in ChromeOS. Just be aware that developing in an OS environment other than Linux, Mac, or a modern version of Windows is likely to offer little in the way of support, so you might be better off using a cloud-based development environment or a virtual machine (VM) environment.

If you have no other options among those that were detailed above and you have sufficient RAM and secondary storage available, then you might consider installing Linux in a VM. Using Linux in a VM will create at least some lag, which might be significant, nevertheless this may be a good choice if you are on an older Windows machine and want to develop off-line. If this describes your use-case, you might try it since it is cost-free. Try VM software such as Virtual Box⁵, installing and running Ubuntu in the VM, and then following the Ubuntu directions above.

If your computer does not have sufficient RAM and enough processing power for properly running a virtual machine, a different option might be to proceed with a dual boot installation with your current operating system and Linux. This method will allow you to start your computer with Linux whenever you need to access your development environment.

To contribute to most open source projects, you will need to set-up a build environment for local testing. While it is typical to have a local development environment to work in, there has recently been an influx of cloud providers which offer solutions for cloud-based development environments. These have the benefit that they require less setup than a local development environment, but are often only free within constraints and otherwise incur a monthly fee, which might be waived for a trial period or for students.

Cloud Development Environments (CDEs) are full development environments in the cloud. The best known and most feature-rich is GitHub Codespaces.⁶ A couple of the other popular cloud development environments include AWS Cloud9⁷ and Gitpod.⁸ All of these environments try to help you set up your development environment with ease, and you can mostly likely find a way to at least try them for free.

For the purposes of this chapter, if you cannot quickly set up your local environment or cloud environment, you can practice using a shell at Fabrice Bellard’s JSLinux⁹ which provides a very small cloud-based virtual machine environment. (Choosing the riscv64 Linux console will work for all of these exercises.) Note that this a free service which has a capped bandwidth of 40 kB/s. You are asked to please be respectful and don’t abuse the service.