A Little About The ‘echo’ Command

That’s right, in today’s article we’re going to learn a little about the ‘echo’ command. We’ll barely be scratching the surface of the ‘echo’ command. There are so many ways to use ‘echo’ that we simply can’t fit it all into an article. Do, read on!

So, what is ‘echo’? Well, basically, the ‘echo’ command is a command that tells the computer to output text – be it in the terminal or using standard output to add that text to a file. It’s useful for regular people, but you’ll find it’s most commonly used in things like bash scripting

That sort of thing, scripting, is outside the scope of this article – and probably beyond the scope of the entire site. Maybe I’ll get to it, but those would end up being long articles, or articles written in parts. Besides, I’m not really all that good with scripting. (If you are good with scripting and would like to write some articles, do let me know.)

This is how the man page describes the ‘echo’ command:

echo – display a line of text

That’s indeed what it does. When you combine it with things like variables, you open up a whole new world. I don’t actually have a very good article about variables, other than existing variables. I should probably have said article.

Anyhow, we’ll just be scratching the surface of the ‘echo’ command. There are all sorts of ways to use ‘echo’, but we’re just going to use it in ways that a new Linux user might use it. Some basic familiarity is probably a good thing.

The ‘echo’ Command:

This article requires an open terminal. If you don’t know how to open the terminal, you can do so with your keyboard – just press CTRL + ALT + T and your default terminal should open. Otherwise, just open your terminal like you normally would.

So, how you start with this ‘echo’ command:

You can also add quotes, and in some cases probably should:

You can also use the > operand and echo the text to a file. Like so:

Read: How To: Write Text To A File From The Terminal with “>” and “>>”

However, that’s not all you can do with the ‘echo’ command. You can also automatically fill in the information by way of environment variables. For example, try this:

Or you can try:

Read: How To: Show All Environment Variables

See? It’s good that I’ve written so many articles. I get to refer to ’em and save us all a bunch of time. So, be sure to visit those articles – especially if you’re a new user. If you’ve forgotten something, you can ‘echo’ the variable to be reminded.

Bonus:

This next bit is really just some information you’re gonna need down the road. I can sense it! This is a bit advanced for some of you, and you won’t need this until later in your Linux journey, but others will see this and suddenly understand the potential. If you’re new, you’ll get there.

The first thing we’re going to do is set a variable. It’s actually very easy to set your own variables in Linux. In this case, we’ll use:

Now, let’s just ‘echo’ the variable you just created:

Or, even better, you can then try:

See? It will output the variable when you echo it. You can create all the variables you’ll realistically ever need. 

You can actually format the output from the ‘echo’ command. For example, the -e flag with the \n separator. An example command looks like:

You can format the text in a variety of ways, just read the man page. You can do quite a lot with the ‘echo’ command and you should definitely check the man page if you’re interested in exploring all the possibilities:

There’s a ton of ways to use ‘echo’ (and with it variables) for those with a clever mind. When you do move on to learn about scripting, you’ll learn that it’s a basic tool used for all sorts of things, in all sorts of clever ways.

Closure:

And there you have it. You have a new article. This time, we’ve covered just the slightest bit of the ‘echo’ command. It’s enough to get your mind working, or so I hope. It’s enough to get a slight taste of the potential and to understand why you may want to be familiar with it.

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your own site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

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How To: Show All Environment Variables

Today’s article is going to show you how to show all your environment variables in Linux. There are quite a few and some of them can be quite useful. If you don’t know what an environment variable is, we’ll cover that briefly as well.

So, what is an environment variable? It’s a static name for a dynamic value. In other words the system has information that varies, but using an environment variable will point to the dynamic information as though it was static.

As an example, we can use ‘echo $PWD‘ in the terminal and it will output the present working directory. If you change the directory and run that command again, it will output the new present working directory. You can do things like ‘echo $SHELL’ and it will tell you the shell you’re using, even if you’ve changed from the default shell. Things like that are the point of having environment variables.

These things really shine when used for things like scripting. They’re useful when you’re not certain of the architecture they’ll be used on and still want the script to work predictably wherever it is used. You’ll also see environment variables put to work in programming. They’re pretty handy, as I said!

If you’d like to see an example, read my article about clearing EXIF data for privacy’s sake. Scroll down to find the alias example I included and you’ll see the $PWD environment variable at work. See? It’s pretty easy and effective. So, let’s see a few ways to show all environment variables.

Show All Environment Variables:

Like most articles, you’re gonna need an open terminal. You can do that with your keyboard, by pressing CTRL + ALT + T and your default terminal should open.

Now that you have your terminal open, we’ll start with the first way to show all the environment variables:

You can also use:

You can also use the following command, but I don’t recommend doing so. It’s here for the sake of completeness and the command will output a lot of gibberish that’s really of no value to the average user.

Now that you know how to show them, here are a few handy examples that further demonstrate what an environment variable does.

Show home with:

Find the system language with:

Or find the desktop environment in use with:

Those are just a few of the environment variables available to you as a Linux user. If you make use of these on a regular basis, please leave a comment explaining how you use them.

Closure:

Yup… Another article. Another step closer to the anniversary of this site. I still have some content to move over from the original site, but writing completely new stuff is pretty fun. Seriously, it’s pretty fun. Please feel encouraged to write an article or two, considering I normally take the whole month of January off!

Thanks for reading! If you want to help, or if the site has helped you, you can donate, register to help, write an article, or buy inexpensive hosting to start your own site. If you scroll down, you can sign up for the newsletter, vote for the article, and comment.

 

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