After copying some files and directories into our home directory (which is a safe bet, because we know for sure that we can write there!), we're left with a little mess. Instead of only creating files, let's use the rm command to remove some duplicate items:

reader@ubuntu:~$ ls -l
total 556
-rw-r--r-- 1 reader reader 550975 Aug 18 14:20 dpkg.log
-rw-rw-r-- 1 reader reader     69 Jul 14 13:18 nanofile.txt
drwxrwxr-x 2 reader reader   4096 Aug  4 16:16 testdir
-rwxr-xr-- 1 reader reader      0 Aug  4 13:44 testfile
-rwxr-xr-- 1 reader reader      0 Aug 18 14:00 testfilecopy
drwxrwxr-t 9 reader reader   4096 Aug 18 14:38 tmp
drwxrwx--- 2 reader reader   4096 Aug  4 16:18 umaskdir
-rw-rw---- 1 reader games       0 Aug  4 16:18 umaskfile
reader@ubuntu:~$ rm testfilecopy
reader@ubuntu:~$ rm tmp/
rm: cannot remove 'tmp/': Is a directory
reader@ubuntu:~$ rm -r tmp/
reader@ubuntu:~$ ls -l
total 552
-rw-r--r-- 1 reader reader 550975 Aug 18 14:20 dpkg.log
-rw-rw-r-- 1 reader reader     69 Jul 14 13:18 nanofile.txt
drwxrwxr-x 2 reader reader   4096 Aug  4 16:16 testdir
-rwxr-xr-- 1 reader reader      0 Aug  4 13:44 testfile
drwxrwx--- 2 reader reader   4096 Aug  4 16:18 umaskdir
-rw-rw---- 1 reader games       0 Aug  4 16:18 umaskfile
reader@ubuntu:~$

Using rm followed by a filename deletes it. As you might notice, there is no Are you sure? prompt. This can actually be enabled by using the -i flag, but by default this is not the case. Consider that rm also allows you to use wildcards, such as * (which matches everything), which will delete every file that is matched (and can be deleted by the user). In short, this is a great way to lose your files really quickly! When we tried to use rm with the name of a directory, however, it gave the error cannot remove 'tmp/': Is a directory. This is very similar to the cp command, and luckily for us, the remediation is also the same: add -r for a recursive delete! Again, this is a great way to lose files; a single command lets you delete your entire home directory and everything in it, without so much as a warning. Consider this your warning! Especially when using in combination with the -f flag, which is short for --force, which will ensure that rm never prompts and starts deleting right away.