2025

After my last blog post about the gloriously pointless /dev/scream, a few people asked:

“Wasn’t /dev/null good enough?”

Fair question—but it misses a key point.

Let me explain: /dev/null and /dev/zero are not interchangeable. In fact, they are opposites in many ways. And to fully appreciate the joke behind /dev/scream, you need to understand where that scream is coming from—not where it ends up.

🌌 Black Holes and White Holes

To understand the difference, let us borrow a metaphor from cosmology.

• /dev/null is like a black hole: it swallows everything. You can write data to it, but nothing ever comes out. Not even light. Not even your logs.
• /dev/zero is like a white hole: it constantly emits data. In this case, an infinite stream of zero bytes (0x00). It produces, but does not accept.

So when I run:

dd if=/dev/zero of=/dev/null

I am pulling data out of the white hole, and sending it straight into the black hole. A perfectly balanced operation of cosmic futility.

📦 What Are All These /dev/* Devices?

Let us break down the core players:

Note: /dev/one is not a standard part of Linux—it comes from a community kernel module, much like /dev/scream.

🗣️ Back to the Screaming

/dev/scream is a parody of /dev/zero—not /dev/null.

The point of /dev/scream was not to discard data. That is what /dev/null is for.

The point was to generate data, like /dev/zero or /dev/random, but instead of silent zeroes or cryptographic entropy, it gives you something more cathartic: an endless, chaotic scream.

aHAAhhaHHAAHaAaAAAAhhHhhAAaAAAhAaaAAAaHHAHhAaaaaAaHahAaAHaAAHaaHhAHhHaHaAaHAAHaAhhaHaAaAA

So when I wrote:

dd if=/dev/scream of=/dev/null

I was screaming into the void. The scream came from the custom device, and /dev/null politely absorbed it without complaint. Not a single bit screamed back. Like pulling screams out of a white hole and throwing them into a black hole. The ultimate cosmic catharsis.

🧪 Try Them Yourself

Want to experience the universe of /dev for yourself? Try these commands (press Ctrl+C to stop each):

# Silent, empty. Nothing comes out.
cat /dev/null

# Zero bytes forever. Very chill.
hexdump -C /dev/zero

# Random bytes from real entropy (may block).
hexdump -C /dev/random

# Random bytes, fast but less secure.
hexdump -C /dev/urandom

# If you have the /dev/one module:
hexdump -C /dev/one

# If you installed /dev/scream:
cat /dev/scream

💡 TL;DR

• /dev/null = Black hole: absorbs, never emits.
• /dev/zero = White hole: emits zeroes, absorbs nothing.
• /dev/random / /dev/urandom = Entropy sources: useful for cryptography.
• /dev/one = Evil twin of /dev/zero: gives endless 0xFF bytes.
• /dev/scream = Chaotic white hole: emits pure emotional entropy.

So no, /dev/null was not “good enough”—it was not the right tool. The original post was not about where the data goes (of=/dev/null), but where it comes from (if=/dev/scream), just like /dev/zero. And when it comes from /dev/scream, you are tapping into something truly primal.

Because sometimes, in Linux as in life, you just need to scream into the void.

It started innocently enough. I was reading a thread about secure file deletion on Linux—a topic that has popped up in discussions for decades. You know the kind: “Is shred still reliable? Should I overwrite with random data or zeroes? What about SSDs and wear leveling?”

As I followed the thread, I came across a mention of /dev/zero, the classic Unix device that outputs an endless stream of null bytes (0x00). It is often used in scripts and system maintenance tasks like wiping partitions or creating empty files.

That led me to wonder: if there is /dev/zero, is there a /dev/one?

Turns out, not in the standard kernel—but someone did write a kernel module to simulate it. It outputs a continuous stream of 0xFF, which is essentially all bits set to one. It is a fun curiosity with some practical uses in testing or wiping data in a different pattern.

But then came the real gem of the rabbit hole: /dev/scream.

Yes, it is exactly what it sounds like.

What is /dev/scream?

/dev/scream is a Linux kernel module that creates a character device which, when read, outputs a stream of text that mimics a chaotic, high-pitched scream. Think:

aHAAhhaHHAAHaAaAAAAhhHhhAAaAAAhAaaAAAaHHAHhAaaaaAaHahAaAHaAAHaaHhAHhHaHaAaHAAHaAhhaHaAaAA

It is completely useless… and completely delightful.

Originally written by @matlink, the module is a humorous take on the Unix philosophy: “Everything is a file”—even your existential dread. It turns your terminal into a primal outlet. Just run:

cat /dev/scream

And enjoy the textual equivalent of a scream into the void.

Why?

Why not?

Sometimes the joy of Linux is not about solving problems, but about exploring the weird and wonderful corners of its ecosystem. From /dev/null swallowing your output silently, to /dev/urandom serving up chaos, to /dev/scream venting it—all of these illustrate the creativity of the open source world.

Sure, shred and secure deletion are important. But so is remembering that your system is a playground.

Try it Yourself

If you want to give /dev/scream a go, here is how to install it:

⚠️ Warning

This is a custom kernel module. It is not dangerous, but do not run it on production systems unless you know what you are doing.

Build and Load the Module

git clone https://github.com/matlink/dev_scream.git
cd dev_scream
make build
sudo make install
sudo make load
sudo insmod dev_scream.ko

Now read from the device:

cat /dev/scream

Or, if you are feeling truly poetic, try screaming into the void:

dd if=/dev/scream of=/dev/null

In space, nobody can hear you scream… but on Linux, /dev/scream is loud and clear—even if you pipe it straight into oblivion.

When you are done screaming:

sudo rmmod dev_scream

Final Thoughts

I started with secure deletion, and I ended up installing a kernel module that screams. This is the beauty of curiosity-driven learning in Linux: you never quite know where you will end up. And sometimes, after a long day, maybe all you need is to cat /dev/scream.

Let me know if you tried it—and whether your terminal feels a little lighter afterward.