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!

1
sl – 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”.

sudo apt install sl #Debian/Ubuntu

sudo dnf install sl #Redhat/Fedora

The sl typo train running in a linux terminal.

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.

sl -l

sl -a

sl -la

man sl #Man page with usage instructions

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

Related

10 Linux Commands to Know for Managing Files

These commands are essential when you’re working with files and directories.

2

2
cowsay – 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.

sudo apt install cowsay

sudo dnf install cowsay

Output from the cowsay command in a Linux terminal

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

cowsay Moo I say to you! Now get back to work.

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

cowsay -f tux Never trust an animal with four stomachs.

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.

cowsay -l #List all defined characters

cowsay --help #Show main help options

3
fortune – 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).

sudo apt install fortune

sudo dnf install fortune

Output from the fortune command in a Linux terminal.

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

fortune

fortune | cowsay

fortune | cowsay -f bud-frogs

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.

Related

Just Starting in the Linux Terminal? Here Are Some Setup Tips

Make your terminal easier to use and more fun!

2

4
yes – 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.

sudo dnf install core-utils

Output from the yes command 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.

yes "I never say no!"

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

yes | program-wanting-answers
yes "no" | program-wanting-answers
Yes "prefer not to answer" | program-wanting-answers

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.

5
rev – Print Anything in Reverse

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

rev comes preinstalled on virtually all Linux distributions.

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

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

echo "Show me this text backwards!" | rev  #Reverse the given input
cat biglongtextfile.txt | rev #Read and reverse a text file
cat input-rev-file.txt | rev > output-rev-file.txt #Reverse input file and save to output file


6
figlet – Generate ASCII Art in Your Terminal

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

sudo apt install figlet

sudo dnf install figlet

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

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.

figlet "I like big letters!"
figlet "Long text will wrap automatically"
figlet -w 120 "The W switch sets the column length of the banner!"
figlet --help

Related

How to Make Beautiful ASCII Art With These Cool Tools

Into the wonderful little world of the oldest digital art format.

7
toilet – 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.)

sudo apt install toilet

sudo dnf install toilet

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

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.

toilet "How-To Geek"#Basic output
toilet -t -f mono12 -F metal "How-To Geek"#Adjust to terminal width
toilet -t -f mono12 -F metal -F 180 "How-To Geek"#Upside down
toilet --help#Show help info

8
cmatrix – Hello, Mister Anderson

Do you dream of being Neo? Recreate the famous dripping green screen from The Matrix in your own terminal.

sudo apt install cmatrix

sudo dnf install cmatrix

Output from the cmatrix program in a Linux 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”.

cmatrix

cmatrix -a

cmatrix -a -b

cmatrix -a -b -r

cmatrix -h #Show help with all options

9
lolcat – 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.

sudo apt install lolcat

sudo dnf install lolcat

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

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.

top | lolcat
figlet "This is lolcat!" | lolcat
ls -la | lolcat
sl | lolcat
lolcat --help#Complete help and usage

10
espeak – 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.

sudo apt install espeak

sudo dnf install espeak

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.

espeak "Welcome to Linux, master!"

espeak -ven+whisper "I am watching you..."

espeak -f <text file to read>

espeak --voices

espeak --help #Complete help and usage

Related

Have Your Linux Terminal Read to You With the espeak Command

Let your terminal start talking today!

3

11
asciiquarium – Swimming and Fishing Prohibited

Get a different underwater view every time you load up the asciiquarium. Don’t worry, you can’t overfeed these fish!

sudo apt install asciiquarium

sudo dnf install asciiquarium

Colorful output of the asciiquarium command in a Linux terminal

There are no special startup options for asciiquarium. While it’s running, the following keys are active:

  • R – Redraw animation (new scene)
  • P – Pause animation
  • Q – Quit asciiquarium

12
oneko – A Cat That Will Chase Your Mouse

Who wouldn’t like a cute, but useless, tiny cat running back and forth across their screen while they work?

sudo apt install oneko

sudo dnf install oneko

Oneko cat chasing the mouse cursor around a Linux terminal

Once oneko is started, hover your mouse cursor over the cat and it will turn into a mouse. Click and hold the left button and the cat will follow wherever you drag the mouse. You can also leave the cat on its own and it will decide when it does or doesn’t want to chase your cursor.

When running, press Ctrl+C in the terminal window where you started oneko to stop it. Here are a few commands to show you some of the options you can set.

oneko #All default settings.

oneko -dog #Make it a dog chasing a bone

oneko -tofocus #oneko runs on focused window

oneko -h #Show complete help and options

13
factor – Prime Factors of Any Number Instantly

Don’t you just hate it when you’re deep into a project, focused and productive, laser-like precision and attention, totally killing it, and then suddenly you realize you can’t continue until you figure out the prime factors of some random 12 digit number?

Yeah, it bugs the hell out of us too. Thankfully—long, loud sigh of relief—there is a quick solution!

Output of the factor command run through figlet in a Linux terminal

Enter “factor” followed by any number at a terminal prompt and get back that number’s prime factors instantly! Try some or all of the following commands to make amazing math tricks in your terminal.

factor 384746133

factor 384746133 | figlet -w 120

factor 384746133 | figlet -w 120 | lolcat

factor 384746133 | toilet -f mono12 -F 180 | lolcat

14
xeyes – Strange Eyes Follow Your Cursor

Just because you’re paranoid doesn’t mean they aren’t watching you. And trust us, they are watching you.

sudo apt install xeyes

sudo dnf install xeyes

Two big eyes from xeyes watching the cursor move in a Linux terminal

Results may vary with this one as the program is quite old. It may not work correctly, or at all, on some window managers or most recent desktop environments. But let’s try anyway.

Just enter “xeyes” at a terminal prompt and two big eyes will appear. Watch them move to follow your cursor. You are amazed! You’re welcome!

15
Watch “echo beep” – Ring the Terminal Bell Infinitely

The “echo beep” command is another that gives us no visual output to show. Go ahead and type the command below to see what it does. Whether or not it will work will depend on the terminal emulator that you are using. It should work with the default terminal for the most common Linux desktops.

watch "echo -e 'a'"

If your terminal app allows for the audible “beep”, you’ll hear it repeat every few seconds. This might not seem very amusing at first, but it makes for a great prank. Start this as a background process on someone else’s Linux terminal and they’ll go mad trying to figure out what is wrong with their system. But hey, you didn’t hear that from us!


None of these commands will ease your workload, make you more productive, or improve your efficiency. They will, however, serve quite nicely the next time you find yourself in the inevitable recurring position all Linux enthusiasts find themselves in from time to time—arguing over useless facts and unnecessary knowledge about Linux and everything it encompasses. This is all just a drop in the bucket, though. There are many hidden treasures to find below the surface of Linux. Keep exploring!