New linux user here. My brother introduced me to it a year or two ago and since I have shunned mac and Windows and only have Debian 10 or Kali on every computer I own.


My questions is this: What are some of the most interesting files in /dev and how can we make practical use of them??


I've already learned how to use /dev/zero with the dd command to basically completely wipe a block device like a hard drive. And I understand that you can use /dev/random to generate random numbers.

What, in ya'll's opinion are some other practical things that can be done with the device files in /dev?


Thanks in advance for the practical insight!


Arc1c_f0x

There's /dev/null -- the "bit bucket"

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And /dev/random.

EDIT: Oops, already said.

Thanks, Scasey I'll start reading about /dev/null !



Hey, Dugan. You might know how I can use /dev/random in a bash script in a specific way.

Let me explain. I'm writing a .sh file called "Bedtime routine.sh". When I execute this file by typing sudo ./Bedtime routine.sh, the program will start, ask how long till I want the computer to shutdown and then play a selection of mozart at random from the mozart directory on my computer. I already completed the first part. My problem now is how might I use /dev/random to supply my program with some sort of value that selects a mozart piece at random from the specified directory?

This is what is looks like so far:

#!/bin/bash
# program that asks shutdown time and plays mozart file at random until shutdown.

echo "Bedtime Routine Program initiated"

echo "Time till computer shutdown?"

read shutdownTimeArg

sudo shutdown $shutdownTimeArg

echo "end of test"

Basically device files i.e. those files in /dev are an interface to a device driver that looks like an ordinary file. They are used for keyboards, mice, hard drives, printers, legacy parallel or serial ports, audio, optical drives. tty terminals, framebuffers and so on.

Those special files like /dev/null are known as pseudo-devices
/dev/null, /dev/random, /dev/urandom, /dev/full or /dev/zero

With modern distributions /dev is a virtual filesystem that exists only in memory and created when the system boots.

The shuf command is an easy way to use random numbers.

^ what does /dev/full do?

There's /dev/urandom, which is /dev/random (one cheesy phrase coming up) "on steroids".
There's /dev/zero, an endless fountain of zeros!
There's /dev/disk/by*, very useful.
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As an aside, don't write a script that requires "sudo" for something so trivial.

Instead, setup sudoers to allows the use access to whichever command requires sudo. It exposes far fewer vulnerabilities.

/dev/full always returns error code ENOSPC i.e. no space left on device. It is used to test programs response to disk full errors.

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Here's an informative link for you, from one of my favorite sites:

http://www.linux-databook.info/?page_id=5108

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What do you mean exactly? That I run the script using sudo as a prefix: "sudo ./Bedtime Routine" , instead of including it in the .sh file itself?

I don't know whether this matters or not with regard to what you said but I am the only user on the aformentioned desktop

Thanks, KGIII. That was a good read

The site's a pretty informative site. It's one of my favorites. I'm still learning new stuff with Linux and that's one of the many awesome resources out there.

I should probably compile a list of the various sites I've found over the years. Hmm... Maybe I'll have time to do that in the near future.

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Sounds like something for the LQ Blog. I’m looking forward to it. 😉

A quick go at your bedtime program. If you generate a text file with all of your desired music files from the desired directory.

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That's not a terrible idea. I've got a few blog articles, all but one written while probably drinking wine! I'm also not willing to maintain another blog for it - or dedicate a terrible amount of time to writing a site just for it. So, that's a good idea and I've got a ton of links. Thanks!