Command Line PSA: Watch out for Traps

There are a few commands that new CLI (command line interface) users should watch out for. Usually it starts with searching for a specific command online and long behold someone has an answer for you on an unknown forum. The command is:

rm -rf /

Or if you are on Windows:

rmdir /S /Q C:\

But please, please do not run these! They will start deleting your entire hard drive. This isn't a funny prank since it has the potential to delete irreplaceable data. Remember to always look up a command before running it! Always be 100% sure that you know what the command will do. On Linux/Unix you can usually man rm (stands for manual) or rmdir /? on Windows. This becomes very valuable since you can quickly double-check your syntax before running a command and often reveals extra options you didn't know existed.

For example, lets try rmdir /? on windows. It returns:

Removes (deletes) a directory.

RMDIR [/S] [/Q] [drive:]path
RD [/S] [/Q] [drive:]path

/S Removes all directories and files in the specified directory
in addition to the directory itself. Used to remove a directory
tree.

/Q Quiet mode, do not ask if ok to remove a directory tree with /S

Notice anything new? Windows has two commands to remove an entire directory, rmdir and rd. So that command above could be replaced with:

rd /s /q C:\

This does exactly the same thing but it's harder to guess that rd stands for "Remove Directory" than rmdir.

Remember, always triple-check your command line entries and be very cautious when seeking answers online.