What does rm -rf do?

What does rm -rf do when used to remove files or directories?

How do the -r and -f options work together?

The command rm -rf is the same as rm -r -f.

From rm's man page (type man rm in a terminal to see it) -r does:

remove directories and their contents recursively

And -f does:

ignore nonexistent files and arguments, never prompt

So in combination they do both.

In fact it is a very dangerous command because it will recursively remove everything within the directory you choose (or just remove the file you choose), and it will do so without ever prompting you.

Please use this command with care!

In addition to the previous correct answer, I would like to teach you how to fish:

When you are not sure about how a command works, what options has and what it does, open a terminal and type

man <command>

For example:

man rm

Once in there, you can search for the option. A man page can be really long to read, so in the terminal type:

/<pattern>

So for example, doing:

/-f

You can easily land to:

-f, --force
              ignore nonexistent files and arguments, never prompt

After typing /-r you'll get:

-r, -R, --recursive
              remove directories and their contents recursively

You can move between search results using n (next) and N (previous).

Bonus:

If you need to do something, but you don't know the command name, use apropos to search in man pages:

apropos <pattern>

For example:

apropos directory listing

rm is short for remove. The r flag is to remove directories and their contents recursively and the f means force, and it overrides any confirmation prompts.

As has already been mentioned, rm -rf <ARG> is meant to forcefully remove files recursively, where <ARG> is a directory ( though it can be a file just fine).

The whole point of -r ( recursive removal ) is that rm cannot remove directories if they aren't empty, simply because the underlying system call which rm uses ( unlink ) operates only on empty directories. Thus, what -r flag does, is depth-first search descending into directories and removing files first, and only then when directory is empty - it will remove it. This same effect is achieved via find command with -delete flag (when you don't specify filtering by -type, but that's another story).

As for -f, it does two things - one prevents prompting for whether you want to remove the file or not (such as when you are removing a file owned by another user from within your directory, it won't show rm: remove write-protected regular empty file 'f1'? confirmation prompt), and ignores non-existing files. So for instance, with a non-existent file name, you should get rm: cannot remove 'nonexistent': No such file or directory error.

See also:

• Why is rm allowed to delete a file under ownership of a different user?
• Doing an rm -rf on a massive directory tree takes hours