13.2. Filesystem and Paths

A filesystem is a structure for the computer to store the files and folders that make up the data of the operating system.

Inside a filesystem, folders are referred to as directories. Folders that exist inside other folders are called subdirectories. A root directory can refer to a few different things but essentially means the top-most directory of a given system. In other words, a root directory is not a sub-directory - but it will probably contain its own subdirectories. Inside the machine you work with called your computer, the root directory is the location of primary hard drive - in Windows, that’s your C drive; in a Mac, the root directory is represented as /. The root directory is the parent directory for the folders stored inside of it.


Most of you have a Desktop folder on your computer. If there is a folder on your Desktop called “LC101_Homework”, then the parent directory of LC101_Homework is Desktop.

A path for files and folders is the list of parent directories that the computer must go through to find that particular item.

Filesystems have two different types of paths: absolute and relative. The absolute path is the path to a file from the root directory. The relative path is the path to a file from the current directory. When working with a relative path, you may find yourself wanting to go up into a parent directory to find a file in a different sub, or child, directory. In order to do so, you can use .. in the file path to tell the computer to go up to the parent directory.


We have a file inside our LC101_Homework directory from the above example. We named that file homework.js. The absolute path for homework.js is /Users/LaunchCodeStudent/Desktop/LC101_Homework for Mac users and C:\windows\Desktop\LC101_Homework for Windows users. If the current directory is Desktop, then the relative path for homework.js is /LC101_Homework for Mac users and \LC101_Homework for Windows users.

Say homework.js is in a different directory called CoderGirl_Homework. CoderGirl_Homework is inside the Desktop directory. Your current directory is LC101_Homework. In this scenario, we would use the .. syntax in our relative path. The relative path would then be /../CoderGirl_Homework for Mac users and \..\CoderGirl_Homework for Windows users.

Many programmers use paths to navigate through the filesystem in the terminal. We will discuss the commands to do so in the next section.