Linux - GeneralThis Linux forum is for general Linux questions and discussion.
If it is Linux Related and doesn't seem to fit in any other forum then this is the place.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Hello,
It has come to my attention that exist commands dangerous of Linux that you NEVER should to realize, for example:
){:|:&};:
This command works as a "Fork Bomb", it operates defining a function called ':', which is called twice, once in the foreground and other in the background, the process repeats indefinitely until the system crashe
Examples of other commands dangerous of Linux that you NEVER should to realize are the following:
Code:
Many novice and experienced Linux users advise to use the command : () {: |: &} ;: in articles and forums?
If yes, please quote all or part of articles and messages that was posted in forums that advise to use the command: () {: |: &};:
I ask to you that to inform me about all or part of articles and messages that was posted in forums that advise to use the command: () {: |: &};: because I want to avoid all the dangerous Linux commands!
The first command of the list of examples of Explainshell is the command ( ){ :|:& };: )
The list of commands of Explainshell is dangerous, irresponsible and malicious. The first command is a fork bomb and that site misleads people by talking about it as something harmless.
The Internet is filled with such bad stuff. They are traps for the unwary.
Edit note added: I'm slow: I started compsing this while Thread on ZRT.
Hello my friend!!! Remember LQ is for more of Q&A, than discussions,
Especially possibly controversial discussions. I hope my suggestion of:
reddit (For more like 'social chat') isn't against LQ rules.
Yes, there's tons of 'damaging' cmds in any os, depending on privs.
That's why I suggested mll. Did you try it, in your VBox? Slackware?
I suggest mimimal Slackware installs, VBox 'snapshots'
Or much easier with mll, because you have only the cd, no hdd!!!
Tell us something we can reproduce, that didn't give the result you expected,
and the exact result differnce. Best wishes for comfort&fun, in all of Life
Edit append: more: @pn: I have a useful question/project for you:
Using mll in a 128MB VBox (no .vdi), with your CPU, how many seconds before it is 'wedged' to the point that Ctrl+c won't work? My N270: a few I think I remember; your cpu probably faster. What ulimit will 'nicely' prevent this? What echo > /{sys,proc}/... ?
Write a nice tutorial about: what reasonable&useful 'setting' could stop a fork bomb, without blocking any other 'reasonable' things?
Hello my friend!!! Remember LQ is for more of Q&A, than discussions,
Especially possibly controversial discussions. I hope my suggestion of:
reddit (For more like 'social chat') isn't against LQ rules.
I posted this topic here in General because General is the correct place to post this topic.
Many novice and experienced Linux users advise to use the command : () {: |: &} ;: in articles and forums?
If yes, please quote all or part of articles and messages that was posted in forums that advise to use the command: () {: |: &};:
I ask to you that to inform me about all or part of articles and messages that was posted in forums that advise to use the command: () {: |: &};: because I want to avoid all the dangerous Linux commands!
The below command is nothing but the first command above (rm -rf). Here the codes are hidden in hex so that an ignorant user may be fooled. Running the below code in your terminal will wipe your root partition.
This command here shows that the threat may be hidden and not normally detectable sometimes. You must be aware of what you are doing and what would be the result. Don’t compile/run codes from an unknown source.
The only "threat" I'm aware of is the "user", ignorant, or otherwise, on a poorly admin'd system.
I've seen 10 Year DBAs drop a db w\out a backup and ask me for it.
I've fork-bombed myself once, just for shits and giggles.
Distribution: Debian Sid AMD64, Raspbian Wheezy, various VMs
Posts: 7,680
Rep:
By the way running "sudo rm -rf /*" doesn't work on most Debian-based systems -- please do not try it outside of a virtual machine though, just in case.
For fun try running Suicide Linux (I think thatKs the name) -- one typo as root and the system wipes itself.
How should I have asked to know the maximum possible of information about dangerous Linux commands?
In my personal opinion, you shouldn't.
The examples given are not dangerous Linux commands, they are examples of short programs contrived for the purpose of causing harm to a Linux system. If you were to ask "How many ways can I break into a Linux system?", the discussion would not be allowed under LQ rules:
Quote:
Posts containing information about cracking, piracy, warez, fraud or any topic that could be damaging to either LinuxQuestions.org or any third party will be immediately removed.
In my opinion, promoting a discusion of "How many ways can I harm a Linux system?", outside any otherwise useful context, should fall under that same rule and not be allowed.
On that basis I am reporting this thread to other moderators for comment and possible action.
How should I have asked to know the maximum possible of information about dangerous Linux commands?
Your question HAS NO ANSWER, because ANYTHING can potentially be harmful/dangerous. Your question is much like asking "Give me a list of ALL the things that can harm a person"...totally open-ended, because everything has the POTENTIAL to be harmful. Whether it is or not depends on the circumstances, system, and conditions.
Quote:
Why? Here is the General of Linux Questions.
Why should you do your own research? Because asking US to do it for you is plain lazy.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.