Welcome to the last and final part of Starting Linux: Hard Mode. This series is a short one, and for a reason. You can’t learn all of Linux in a few blog posts. I’ve been using it for several years, and I’m still learning new things about it. This final part explains what a shell is and what other distros are like, but more importantly, it shows you how to teach yourself, and how to find more help.

The Shell

In the last couple of sections, I’ve used the term “terminal” when describing what we’re using to use commands. In reality, what we’ve been using is a shell. A shell is a program like any other, while the terminal is what runs a shell. It’s the software that decides how we enter commands, and what happens when we submit them. It’s also the software that handles environment variables and allows you to navigate your filesystem.

There are many different shells, some that work the same way that we’ve been learning, and some that do things entirely differently. Like Linux, you can group them into families. The shell that we’ve been using is called ash (Alpine Shell), and you will get near-identical functionality in bash (Basic Shell), and zsh (Z Shell). You can consider them all to be in a family because they’re all based on a shell called the Bourne Shell. You also have csh (C Shell) and tcsh (T C Shell), the latter derived from the former. Finally, you have exotic shells such as fish (Friendly, Interactive Shell), which are their own thing entirely.

All of these different shells have their merits, and I think it’s worth exploring them all at one point. However, when starting with Linux, I’d stick with shells within the same family, as they’re almost always near-identical. While most concepts carry over to each one and commands work the same consistently, you may be surprised with some features you find either missing or added when compared to one you’ve been using. As a simple example, fish doesn’t have the export keyword.

Each shell also has a scripting language, which you use when you type in any command. Take redirects, for example. Redirects aren’t a program like most other commands are; instead, it’s a function defined by the shell. There are several other examples of commands defined by the shell, such as the export keyword. Since this isn’t a programming tutorial, I won’t go in-depth on how to do shell scripting, but you should research it separately when you can. It’s a potent tool that you can use to automate a lot of work in the terminal.

In the previous section, you’ve done some shell scripting already when you modified ~/.profile to persist an environment variable. In doing that, you leveraged the power of shell scripting to accomplish a task that previously wouldn’t have been possible. Every shell has configuration files that get loaded when a user logs into their system. Common to all shells within the same family as ash is ~/.profile. However, bash and zsh also offer ~/.bashrc and ~/.zshrc respectively. These files are the preferred files to edit when trying to perform initial setup after login.

Of all the shells available, bash is by far the most used. It is the default in Debian and RedHat based distros, which comprise a large part of all distros. Fortunately, if you’ve been following this series, ash is near-identical to bash because they’re in the same family. You won’t find any significant differences. If you’re unsure of what shell you’re using, $SHELL holds the value of your system’s default shell (the one that you log into).

Swapping Distros

While Alpine is fantastic and I love it, it’s not a Linux distro for general use. It shines brightest when combined with a tool called Docker or for servers. Instead, you’ll likely want to use a Debian or RedHat distribution (although there are plenty of other great ones). In my opinion, the RedHat distributions are great for work, while Debian distributions are best for home use. For example, I used Fedora at work and Pop!_OS at home.

Every Linux distribution is still Linux, don’t worry. The fundamentals won’t change, such as the filesystem and users. What will change is the default tools that are present and how they use the filesystem. Take package managers, for example. Every operating system worth its salt has one, but every family uses a different one, and they store their data in different places. Fortunately for you, you don’t have to worry about where they store the data in most cases. You only need to know how to use it.

In RedHat distributions, the package manager provided to you is either yum or dnf. The latter is the newest and preferred tool and is available on any modern distributions like Fedora. The former is old and is all that’s available on the more outdated platforms. Both tools operate almost identically, and the subcommands for both of them are the same. With either, to install a package, run X install Y where X is yum or dnf, and Y is the package to install.

In Debian distributions, the package manager provided to you is apt. It’s a weird one because it’s broken into multiple commands. For example, if you want to install or remove a package, you use apt-get, and if you’re going to modify the cache, you use apt-cache. More recently, they created apt, which includes all the most common operations, and is the preferred command to use. Like yum or dnf, to install a package, you would run apt install X, where X is the package to install.

A significant difference between Alpine and these other distributions is the addition of a desktop environment. A desktop environment is what allows you to interact with Linux graphically, like any other operating system. The most popular desktop environment is GNOME and is the default for Debian and RedHat distributions. Working with GNOME is an entirely different guide, but it’s designed to be intuitive, and I think it does an excellent job at that. If you ever get lost, every desktop environment comes with a terminal emulator. It’s an application called “Terminal” that allows you to use the default shell as we have been through this guide. You can also have a straight terminal session that looks like what we’ve been using by pressing CTRL-ALT-X, where X is F3, F4, or F5. These key combinations switch your Linux session. By default, you have two graphical sessions and 3 terminal sessions. You can change back to the graphical session with CTRL-ALT-F2 or CTRL-ALT-F2. You typically start on the F2 session. Switching to these terminal sessions are a great way to fix problems with the graphical ones, such as freezing, or if you want a terminal-only experience.

Other than the addition of a desktop environment and a different package manager, most of the Linux experience remains the same. Everything that you’ve learned this far will carry over. However, some great tools are unique to these distros for you to leverage, and you should research what they provide to you. The more tools you know about and can leverage, the easier your life becomes.

Extending Commands

So far, we’ve used several commands, and there are many more, but we haven’t even remotely used them to their full potential. I could make an entire post on each command in isolation due to how versatile they all are. However, I’ll use the ls command as an example, as the concepts I go over here will extend to every other command.

Common amongst almost every command is the --help flag. This flag will describe the most useful flags that are available to it, as well as any subcommands that exist. Let’s try calling ls --help to see the help for ls:

As you can see, there are so many options that we can’t even see them all! To scroll up in the terminal, press SHIFT-PAGE UP, and to scroll down, press SHIFT- PAGE DOWN. We can see the -a flag that we used in part one, and we can also see a variation of it that we haven’t seen before: -A. It’s a useful flag because we already know that . and .. exist, and we don’t need them to clutter up out output. Every command has many flags, and it’s worth looking at the help for each one and trying them out to see what each one does. As an exercise to you, check out the -l flag, which is used to see who owns a file and more.

Linux also has a manual that we can read to get even more information about a command. On most systems, the manual is already available by default; however, it isn’t on Alpine. To install it, install the man and man-pages packages with apk. To view the manual on any command that provides it, run man X, where X is the command for which you want the manual. For example, if you need to read the manual for man, run man man (yes, really). The manual is handy, but it is hard to read, and I suggest, if you can get away with it, to use the --help flag when starting in Linux. If you decide that you do want to explore the manual, definitely read man man first. I would also suggest not reading Alpine’s version, as it doesn’t display all the characters right. You can also google the manual for any command, as several sites provide the pages as HTML. For example, here is the man page for ls.

Conclusion

Through all of this, we haven’t even touched the surface of what Linux can do. We haven’t learned the super-powerful commands such as grep, vim, or tmux, yet, you already know so much more than most computer users. This guide’s purpose was to introduce you to Linux and the terminal. From here, all you have to do is keep using it, and through that, you’ll learn everything you need to know as each problem comes up. Learning is a journey unique to each person, and only you can teach yourself properly.

With that said, I’ll be writing posts on individual commands and concepts in the future, so be on the lookout to expand your arsenal!