From your everyday talking cows to upside-down, rainbow-colored, ASCII art made from ridiculously large prime numbers, these Linux commands range from mildly humorous to outright bizarre. Just because these commands are useless doesn’t mean you shouldn’t use them!

1sl - The Typo Train is Coming

Let’s first clarify that this command is lowercase “S” and “L”, sl. The intent of this command is to provide a somewhat comical indication that you’ve mistyped the common Linux directory listing command, “ls”.

Once installed, simply enter “sl” at the terminal prompt to make the train run. To make it a bit more interesting, sl also shows different variants of the typo train if some of the more common ls command line switches are used.

The sl typo train running in a linux terminal.

If you know somebody who makes this mistake often, the typo train will help them break their bad habit fast!

2cowsay - Talking Cows (and More!)

Linux has always had a somewhat strange and ongoing relationship with a few specific animals—cows being one of them. (No offense to the penguins or the llamas.) In the spirit of creating absolutely useless yet entertaining programs, cowsay was released to the world.

To make the cow speak, enter any phrase after the cowsay command.

Output from the cowsay command in a Linux terminal

Bored with the cow and want to make Tux talk? You can do that too.

There are also plenty more characters who will let you put words in their mouths. To see what else you can do with cowsay, try entering the following commands.

Output from the fortune command in a Linux terminal.

3fortune - Random (and Sometimes Profound) Wisdom

Fortune is one of the more self-explanatory items on this list. Think of it like being able to crack open a fortune cookie any time you want, right in your terminal (minus the preliminary delicious meal—and the tasty, crunchy cookie).

Asking for a new fortune is as simple as typing “fortune” at the command line. If you’re creative, you’re able to even pass the output of fortune to other programs—for example, cowsay. Try the following commands.

Output from the yes command in a Linux terminal.

If you’re a bit creative with shell scripts, you can also set things up so that you are greeted with a new fortune each time you open (or exit) a terminal.

4yes - Print Yes (or Anything Else) Into Infinity

This one might just be truly useless at this stage of Linux evolution. By default, “yes” will simply print the letter y infinitely. This could be useful to automatically answer yes to programs that ask lots of yes/no questions. You can also add your own arbitrary phrase and that will be printed repeatedly and infinitely until you stop it.

This should be available on Ubuntu by default. For rpm based distributions, you may need to install it with the following command.

Output from the rev command running on a text file in a Linux terminal

Once installed, typing “yes” by itself at a command prompt will output an endless stream of lowercase Y’s. You’ll need to hit Ctrl+C to stop the output. You can also give it a custom phrase to repeat.

To use it to answer questions coming from a program you don’t have enough patience for,run it through a pipelike this:

Output of figlet printing Read How-To Geek in a Linux terminal

Using the “yes” command can potentially cause CPU-intensive or memory-filling loops requiring a hard reset of your computer to escape. You should not experiment with it while you have any important tasks running or unfinished work of any kind.

5rev - Print Anything in Reverse

The rev command will take any text input from you and spit it back out in reverse order. you’re able to pass short snippets of text directly at the command line or feed it entire text files.

rev comes preinstalled on virtually all Linux distributions.

Pass text at the command line or have rev reverse an entire file with the following commands.

6figlet - Generate ASCII Art in Your Terminal

Generate old school ASCII text banners right in your terminal with figlet.

Once installed, simply type “figlet” followed by any text you want. Try the following commands to get an idea of what you can do with it.

Output of toilet command printing Read How-To Geek in a Linux terminal

7toilet - ASCII Art with Colors and Fonts

If figlet wasn’t enough to blow your mind, check out toilet! (Yes, that really is the name. No, we don’t know why.)

Toilet takes things to a higher level, allowing you to add color and fonts to your terminal text banners. There are plenty of options to explore if you are in the mood. Here are a few quick commands to get you started.

Output from the cmatrix program in a Linux terminal.

8cmatrix - Hello, Mister Anderson

Do you dream of being Neo? Recreate the famous dripping green screen fromThe Matrixin your own terminal.

But wait! There’s more! Use the following commands to create different variations of the original Matrix terminal. Press Ctrl+C to exit and return to “reality”.

Output of lolcat command printing We Love How-To Geek in a Linux terminal.

9lolcat - It’s Like Rainbow Sprinkles for Your Terminal

Somewhat similar to figlet and toilet, lolcat takes your bland and lifeless input and creates hypnotizing, eye-dazzling output.

Using lolcat on a single line of text doesn’t really do it justice. This entry on our list of useless commands works best if you pass the output from another program into it. To get a quick idea of what lolcat will do, try some of the following commands.

10espeak - Make Your Computer Talk in Creepy Voices

Your terminal can talk to you, though don’t expect it to sound anywhere as natural as the text-to-speech tools on your phone. Install espeak easily if it’s not already there.

I don’t have a screenshot since this useless command only generates audio. Try a few of the following commands and look through the help to find combinations to make your own unique voices.