Lunduke
News • Science & Tech
The Fork Bomb: What it is, how it works, and where it originated
The idea started in 1969... and it's been causing computers to crash ever since.
December 03, 2023
post photo preview
:(){ :|:& };:

That simple line has been crashing systems in the Linux world for years — It is known as the (infamous) “BASH Fork Bomb”.

When run in a GNU/BASH shell, this BASH variant of the Fork Bomb will bring your average Linux system to its knees, lickety-split. A mere handful of characters that can cause a computer to cry “Uncle.”

But what, exactly, is a “Fork Bomb”? How do they work? And where on this green Earth of ours were they first created?

Come with me on a journey into the history, design, and usage of one of the most dastardly ideas in all of computing… of The Fork Bomb!

What is a Fork Bomb?

The idea of a Fork Bomb is simple: Create a piece of code that does one thing and one thing only: replicate running instances of itself. And do so as quickly as possible.

Here, a visual will help drive the idea home.

In this case each Bunny Rabbit represents one instance of the Fork Bomb. Each bunny makes two new bunnies. Quickly. Multiplying like, well, rabbits.

Each of those adorable little bunny rabbits may not take up much RAM… or much CPU time… but imagine 20 of them. Or 1000. Or, like, a bazillion?! That Fork Bomb will continue making running copies of itself just as long as the system allows it to (by continuing to have available memory or not fully crash).

With how quickly each Fork Bomb replicates itself… and the number of copies growing exponentially… you can see how they can become a problem in a hurry. Often causing a system to lock up quicker than you can say, “Maybe I shouldn't have pressed Enter.”

A real-world example… and how it works

Let’s take a look at that BASH version of the Fork Bomb again (as that is one of the most popular and famous examples).

(If you don’t know how BASH scripting works, no worries. I’ll break it down… make it nice and easy.)

:(){ :|:& };:

Ok. So how does this, ridiculous looking, collection of semi-random seeming characters, actually work?

Let’s break that apart into multiple lines to make it all easier to read.

: ( ) {

   : | : &

} ; :

This… is a BASH script function.

But there’s something… weird about it. Note the many usages of “:”? In this case “:” is being used as a function name.

“Why is using “:” as a function name weird,” you ask?

Because, on most UNIX-y systems, it is not allowed to use a character in a function name other than letters and numbers (and underscores). But the GNU version of BASH — which is commonly used on oh-so-many Linux systems — allows : and so many other characters to be used.

Why does GNU allow a “:”? Who knows. GNU be crazy.

Regardless…

Let’s replace the “:” in that BASH script with “rabbit”. That will, in addition to making it run on more UNIX systems, make this a bit easier to read.

rabbit() {
rabbit | rabbit &
}; rabbit

There. So much better. Here we go. Line by line.

Line 1: rabbit() {

That first line does something simple. It defines a function named “rabbit”. That’s it and that’s all.

Line 2: rabbit | rabbit &

Line 2 is the insidious part.

It calls the function named “rabbit”, and sends the output of that function to the function named “rabbit.”

But, here’s the thing, there really isn’t any output of the “rabbit” function. So this is really just a fancy way of calling the “rabbit” function twice… at the same time.

Yeah. The “rabbit” function calls itself, from within itself, then calls itself again.

Oh, and that “&” at the end? That's the BASH way of telling “rabbit” to run in the background.

The net result? Every “rabbit”, makes two new “rabbit”s.

Line 3: }; rabbit

That last nine simply ends the “rabbit” function… and then calls itself.

Note: I highly recommend not running this code on your system unless you do so in a virtual machine. Without taking the proper precautions… this will bring your system to its knees.

Every variation of a Fork Bomb operates in a roughly similar fashion. A small piece of code that creates copies of itself… repeatedly. Thus eternally replicating itself until the system runs out of resources.

The first Fork Bomb

The very first known usage of a “Fork Bomb” was way back in 1969 at the University of Washington.

There, a Burroughs B5500 computer had been installed three years earlier. A big computer that provided the first time-sharing system on the University of Washington campus (through a series of dial-up modems running at 110 baud). This was also the first computer at the University of Washington to provide disk storage for user files. Pretty cool.

A Burroughs B-5500. Not the one at the U of W, though. Classy looking machine, right?

On that big, beautiful Burroughs B-5500, someone reportedly wrote a small bit of code that would make two copies of itself — over and over again — until the memory of the machine was full and the entire system would crash.

That intrepid programmer named that tiny little program, appropriately: “RABBITS”

Fun historical tidbit: RABBITS for the Burroughs B-5500 was not, technically the first computer virus. That distinction appears to go to the 1971 “Creeper Virus”. While RABBITS predated Creeper by a good two years… RABBITS doesn’t really act like a virus. It requires a user to explicitly run it in order to cause its own mischeif.

The 1974 “Wabbit”

A similar piece of code was written on an IBM System/360, a few years later, in 1974. Clearly inspired by “RABBITS”, this new code was called “Wabbit” and was, as Elmer Fudd might say, quite “wascally”.

The IBM System/360 Model 22 control panel. That thing was awesome looking.

Legend has it that the individual who created “Wabbit” ran the program on the System/360 at work… causing the entire system to crash. The man, again according to legend, lost his job.

Fun bit-o-trivia: As years went on any program that would self-replicate when ran by the user… but wasn’t actually a virus… would become known as a "wabbit.” in honor of this particular event.

Some other variations on the Fork Bomb

There have been Fork Bomb type bits of code written in just about every language you can imagine. At the beginning we covered how to write a Fork Bomb in BASH. But, because this sort of mayhem is simply too much fun, below you will find code to create similar bits of functionality in several other programming languages.

Enjoy.

Just… you know… try not to get yourself fired.

Fork Bomb in C:

int main(void) {
for (;;) {
    fork();
}
}
Fork Bomb in Python:

#!/usr/bin/env python

    import os
    while True: os.fork()

Fork Bomb in Ruby:

#!/usr/bin/env ruby
loop { fork { bomb } }
community logo
Join the Lunduke Community
To read more articles like this, sign up and join my community today
6
What else you may like…
Videos
Podcasts
Posts
Articles
February 13, 2025
Fedora's Code of Conduct: 200 Day Response Time, Only Protects You if Red Hat Likes You

Lunduke tests Fedora Linux's Code of Conduct. The results are just as ridiculous as you'd expect.

00:17:20
February 13, 2025
Lunduke Journal's New Self-Hosted Forum, Telnet BBS

So many ways to enjoy The Lunduke Journal now -- X, YouTube, Rumble, Substack, Podcast & more -- plus two new (self-hosted) ways to interact with the community.

More from The Lunduke Journal:
https://lunduke.com/

00:17:09
February 12, 2025
Codeberg Announces "Fight Against Far-Right"

The Git source code hosting organization, in response to anonymous spam, declares war on "Right-Wing Forces", encourages others to do the same.

00:17:56
November 22, 2023
The futility of Ad-Blockers

Ads are filling the entirety of the Web -- websites, podcasts, YouTube videos, etc. -- at an increasing rate. Prices for those ad placements are plummeting. Consumers are desperate to use ad-blockers to make the web palatable. Google (and others) are desperate to break and block ad-blockers. All of which results in... more ads and lower pay for creators.

It's a fascinatingly annoying cycle. And there's only one viable way out of it.

Looking for the Podcast RSS feed or other links? Check here:
https://lunduke.locals.com/post/4619051/lunduke-journal-link-central-tm

Give the gift of The Lunduke Journal:
https://lunduke.locals.com/post/4898317/give-the-gift-of-the-lunduke-journal

The futility of Ad-Blockers
November 21, 2023
openSUSE says "No Lunduke allowed!"

Those in power with openSUSE make it clear they will not allow me anywhere near anything related to the openSUSE project. Ever. For any reason.

Well, that settles that, then! Guess I won't be contributing to openSUSE! 🤣

Looking for the Podcast RSS feed or other links?
https://lunduke.locals.com/post/4619051/lunduke-journal-link-central-tm

Give the gift of The Lunduke Journal:
https://lunduke.locals.com/post/4898317/give-the-gift-of-the-lunduke-journal

openSUSE says "No Lunduke allowed!"
September 13, 2023
"Andreas Kling creator of Serenity OS & Ladybird Web Browser" - Lunduke’s Big Tech Show - September 13th, 2023 - Ep 044

This episode is free for all to enjoy and share.

Be sure to subscribe here at Lunduke.Locals.com to get all shows & articles (including interviews with other amazing nerds).

"Andreas Kling creator of Serenity OS & Ladybird Web Browser" - Lunduke’s Big Tech Show - September 13th, 2023 - Ep 044

FUTO is putting on a “Don’t Be Evil” event during SXSW.

March 15th. Myself. Louis Rossman. Andreas Kling.

It’s going to be nerdy. And, guaranteed, it’s going to be talked about.

https://partiful.com/e/iI0zo1ewEu0YP4ii5XWF

post photo preview
post photo preview
post photo preview
February 13, 2025
For February: 50% off Subscriptions, 50% off DRM-Free Downloads, Lifetime Subscriptions available

2025 is off to an amazing start for The Lunduke Journal.

The number of people getting their Big-Tech-Free Tech News from The Lunduke Journal is shooting through the roof. Subscriptions (of every kind) are soaring.

And The Lunduke Journal is now available on a wide variety of platforms — with our core community area now consolidating on our own, self-hosted forum (which is exclusively available to subscribers).

With the tidal wave of new people — many of you wanting access to the new, exclusive Forum — I want to make it as easy as possible for everyone to become a part of what we are doing. Time to do something a bit crazy. Massive discounts on subscriptions (I mean… huge). For the entire month of February.

Yup. The whole gosh darned month.

If it’s February, the discounts below are all available. Choose whatever works best for you. Then feel awesome about supporting truly independent Tech Journalism.

50% Off Yearly Subscription:

50% off a Yearly subscription to The Lunduke Journal via both Locals and Substack. (This includes full access to the community Forum.)

That’s $2.25 per month. Pocket change.

50% Off DRM-Free, MP4 Downloads:

Want to be able to download every show The Lunduke Journal releases (and watch them on whatever device you like)? Yeah. You can do that. For 50% off.

Note: This DRM-Free download option does not include access to the Forum. This option is strictly for downloading the episodes.

The Famous Lifetime Subscription:

The "World Famous Lunduke Journal Lifetime Subscription" is exactly what it sounds like. Pay once and get full access to The Lunduke Journal. For life. A great way to support Big-Tech-Free Journalism.

(This includes full access to the community Forum.)

New Lifetime Subscriptions are available, for $200, from now through February 28th.

The Lifetime Subscription can be obtain via Locals, Substack, or using Bitcoin. All three options work great and are super easy.

How to get a Lifetime Subscription via Locals:

  1. Go to Lunduke.Locals.com/support.

  2. Select "Give Once".

  3. Enter "200" into the amount field.

  4. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

How to get a Lifetime Subscription via Substack:

  1. Go to Lunduke.Substack.com/subscribe.

  2. Select the “Lifetime Subscription” option.

  3. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

If you would also like full, Lifetime access to Lunduke.Locals.com (which is included):

  1. Make a free account on Lunduke.Locals.com.

  2. Email “bryan at lunduke.com” with the email address you use on both Substack and Locals (can be different email addresses).

  3. Lunduke will toss you an email once your account is set to full lifetime status on Locals.

How to get a Lifetime Subscription with Bitcoin:

And, finally, you can obtain a Lifetime Subscription via Bitcoin. Save a few bucks with this option, as Bitcoin processing has fewer fees associated with it.

bc1qyjakve8fywm8pz2v99v57yhjj0vzr2vjze6fcq

  • Email "bryan at lunduke.com" with the following information: What time you made the transaction, how much was sent (in Bitcoin), and the email address you use (or plan to use) on Locals.com.

The Lunduke Journal would not be possible without your support. Every subscriber, of every type, makes a massive difference in bringing Big-Tech-Free Tech Journalism to the world.

Thank you.

-Lunduke

Read full Article
February 09, 2025
post photo preview
The Great Tech Demographic Survey of 2025

There are a lot of questions we don't have good answers for.

  • Do Trump voters prefer EMacs or Vi?
  • Who is happier with their life... people who use Tabs or Spaces?
  • Does your age impact your choice of Web Browser?
  • Who is more likely to support censorship... Rust Programmers or C Programmers?

Do you know the answers to those questions?  No, I don't either.

Let's find out.

The Great Tech Industry Demographic Survey of 2025

This survey is massive -- containing questions on everything from Operating System preferences to religion and politicsProgramming languages and... workplace discrimination.  It even gets into Cryptocurrency and Text Editor preferences.

Seriously.

  • All answers are 100% anonymous (no account is needed), no email address is collected.
  • All questions are optional (only answer the ones you feel comfortable with).
  • The questions are all presented in random order.
  • All of the (anonymous) results will be published.

The 2024 edition of this survey (last year) was taken by over 7,200 people across the entire IT industry -- an absolutely massive sample size (larger than most US Presidential Election polls).  For this new 2025 survey... we're aiming even higher.

Are you a computer nerd?  Do you work in the IT industry?

Set aside a few minutes and take the 2025 survey.

Then tell everyone about it.  The more people who take the survey -- across as many companies and communities as possible -- the better the data will be.

Read full Article
February 03, 2025
Fund Indie Tech Journalism. Lifetime Subs & Discounts available for 48 hours.

February is upon us! And — would you look at that — thanks to all of you, The Lunduke Journal is already fully funded through the end of February!

That means: We can continue to have zero sponsors, zero advertising and, even more importantly, zero influence from Big Tech.

Now. How amazing would it be if The Lunduke Journal could reach our funding goals through the end of March… almost two months ahead of time? Pretty freaking amazing. And absolutely doable.

Let’s do it.

Through Tuesday (February 4th), we’ve got a handful of discounts on Lunduke Journal subscriptions. Take a look. A huge thank you to everyone who has already subscribed — you make this all possible.

Every penny goes towards keeping truly independent journalism alive.

Lunduke Journal Discounts

For the next 2 days (through Tuesday, February 4th), in addition to regular subscriptions, you can grab two limited discounts:

  1. Discounted Lifetime Subscriptions (scroll down for details)

  2. DRM-Free, MP4 Downloads for 2024 & 2025 (combined) for 55% off.

There many ways to support The Lunduke Journal. Choose the option that makes you smile. It’s all listed below.

Where to grab a Monthly or Yearly Subscription:

These are regular price. But still awesome.

Lifetime Subscription Details:

  • Pay once, full subscription for life (on Locals, Substack, or both).

  • Available only until Tuesday, February 4th. Then the Lifetime Subscription option goes “back in the vault”.

  • Can be purchased via Locals, Substack, or with Bitcoin. Chose whichever works for you. Scroll down for steps.

Where to buy a DRM-Free, MP4 video yearly download pass:

Want to be able to download every show The Lunduke Journal releases (and watch them on whatever device you like)? Yeah. You can do that.

The Famous Lifetime Subscription via Locals:

The "World Famous Lunduke Journal Lifetime Subscription" is exactly what it sounds like. Pay once and get full access to The Lunduke Journal (with all the perks of subscription on Locals). For life.

New Lifetime Subscriptions are available, for $200, from now through February 4th. Then this option goes "back into the vault".

Here's how to grab one of these coveted bad boys for yourself:

  1. Go to Lunduke.Locals.com/support.

  2. Select "Give Once".

  3. Enter "200" into the amount field.

  4. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

The Famous Lifetime Subscription via Substack:

You can also snag a Lifetime Subscription via Substack:

  1. Go to Lunduke.Substack.com/subscribe.

  2. Select the “Lifetime Subscription” option.

  3. After checking out, Lunduke will toss you an email once your account is set to full lifetime status. (This usually happens within a few hours.)

If you would like full, Lifetime access to Lunduke.Locals.com (which is included):

  1. Make a free account on Lunduke.Locals.com.

  2. Email “bryan at lunduke.com” with the email address you use on both Substack and Locals (can be different email addresses).

  3. Lunduke will toss you an email once your account is set to full lifetime status on Locals.

The Famous Lifetime Subscription (with Bitcoin discount):

And, finally, you can obtain a Lifetime Subscription via Bitcoin. Save a few bucks with this option, as Bitcoin processing has fewer fees associated with it.

  • Make sure you have a Lunduke.Locals.com account (a free account works just fine).

  • Send $190 worth of Bitcoin (or more) to the following address:

bc1qyjakve8fywm8pz2v99v57yhjj0vzr2vjze6fcq

  • Email "bryan at lunduke.com" with the following information: What time you made the transaction, how much was sent (in Bitcoin), and the email address you use (or plan to use) on Locals.com.

Once again, thank you. The Lunduke Journal would not be possible without your support.

You rule. Seriously.

-Lunduke

Read full Article
See More
Available on mobile and TV devices
google store google store app store app store
google store google store app tv store app tv store amazon store amazon store roku store roku store
Powered by Locals