Rm (Unix)

  (short for remove) is a basic command on Unix and Unix-like operating systems used to remove objects such as computer files, directories and symbolic links from file systems and also special files such as device nodes, pipes and sockets, similar to the  command in MS-DOS, OS/2, and Microsoft Windows. The command is also available in the EFI shell.

Quotes

 * You can use rm -rf dir to delete a directory and its contents, but be careful! This is one of the few commands that can do serious damage, especially if you run it as the superuser. The -r option specifies recursive delete to repeatedly delete everything inside dir, and -f forces the delete operation.