While there are thousands of discoveries to make just exploring your filesystem, we are going to move on to making your own modifications. The two basic operations we need are creation and destruction

Note: There are far fewer safety features in the terminal compared to the regular GUI. If you ask the terminal to delete something, it will. No questions asked. And there is no trash can where you can recover something that you accidentally deleted. Please think before you type.

There are two types of objects in the filesystem: files and directories (or folders depending on who you ask). Files hold data, like pictures, songs, essays, or apps. Directories hold files; they are just there for organization.

Returning to where we left off, let’s open a terminal and run cd – short for “change directory” – to move to our “home” directory. Your home directory and everything inside it belongs to you. You are free to create, destroy, or edit anything you find there.

Directories

We don’t want to accidentally delete or change anyone’s important files, so we’ll start by creating a directory to play in. I’m going to call my directory “projects”, but if that name is already taken on your computer, feel free to use something else.

$ cd
$ ls
Applications  Documents  Pictures
Desktop       Downloads
$ mkdir projects
$ ls
Applications  Documents  Pictures
Desktop       Downloads  projects

Following the pattern of simple command names, mkdir makes a new directory for you.

Try running that mkdir command again exactly as you did the first time.

$ mkdir projects
mkdir: cannot create directory ‘/home/patrick/projects’: File exists

This time, mkdir fails and prints an error. It was unable to make the directory I asked for (/home/patrick/projects) because it already existed (File exists). If you saw this error the first time you ran the command, check what directories already exist with ls and then pick a name that isn’t being used.

To remove a directory, run rmdir.

$ rmdir projects

This command fails in two common ways:

$ rmdir asdf
rmdir: failed to remove '/home/patrick/asdf': No such file or directory

$ rmdir projects
rmdir: failed to remove '/home/patrick/projects': Directory not empty

The first failure tells us that rmdir could not remove asdf because there were no files or directories with that name.

The second failure tells us that rmdir could not remove projects because that directory still had files or other directories inside of it. rmdir will only work on completely empty directories.

Files

Reset to your home directory and recreate the “projects” directory if you deleted it earlier. Then cd into it.

$ cd
$ mkdir projects
$ cd projects

Now that we have a directory to work in, we can start working with files. First, we can create them with touch.

$ touch bob.txt
$ touch test.html
$ touch example.pdf
$ touch 10
$ touch directory
$ ls
10  bob.txt  directory  example.pdf  test.html

touch creates an empty file with whatever name you provide. There are not many restrictions on what you can name files, but I would recommend that you:

• avoiding using / and spaces
• name files descriptively

/ and spaces can mean different things, which can cause some confusing issues. And naming a file something like “directory” is a bit misleading. It is best to be as clear as possible; future you will thank you.

To remove files, use rm.

$ rm bob.txt
$ rm test.html
$ rm example.pdf
$ rm 10
$ rm directory
$ ls

Again, please be careful with rm. There are no warnings or backups, the file is gone forever.

Your Toolbox

With two tweaks, you will know everything you need to know about the filesystem.

First, we can replace rmdir with rm -r. Many commands accept optional “flags” that modify how they work. For rm, the -r flag tells it to delete “recursively”, which means directories and everything inside them.

Second, we need a method of writing data into files. touch creates files, but they are empty. We are going to replace touch with vim, which can both create and edit files.

Your toolbox for interacting with the filesystem will look like this,

# Navigating
- ls
- cd
- pwd

# Managing Directories
- mkdir
- rm -r

# Managing Files
- vim
- rm