What is a file path?

Your computer has hundreds of thousands of files. When you want a specific one, you can’t just say “the photo.” You have to give the computer an address.

That address is called a path.

How an address works

Think about how you’d describe where a book is in a library:

Second floor → History section → Shelf 14 → third book from the left.

Each step narrows things down until you’re pointing at exactly one book. A file path is the same — folder, then folder inside it, then folder inside that, then finally the file:

Documents/work/2025/report.pdf

Read it left to right:

1. Start in a folder called Documents.
2. Inside it, open work.
3. Inside that, open 2025.
4. There’s a file called report.pdf. That’s the one.

The / between each piece is the separator. It just means “now go inside this one.”

Slashes: which way?

You’ll see two:

• Forward slash / — used on Mac, Linux, the web, and most documentation.
• Backslash \ — used in old Windows paths and File Explorer’s address bar.

Modern Windows accepts both. This course uses forward slashes everywhere, and so does Claude.

What a real path looks like

On different operating systems, the very start of a path differs:

Mac:     /Users/you/Documents/report.pdf
Linux:   /home/you/Documents/report.pdf
Windows: C:\Users\you\Documents\report.pdf

Different roots, same idea: a chain of folders ending in a file.

You already use paths

Every time you click a folder, then a folder, then a file in Finder or File Explorer — you’re walking a path. A written path is just that same journey put into words.

Why bother writing it down? Because a path is how you point at one exact file without anyone having to guess. When you tell Claude “look at Documents/work/2025/report.pdf,” there’s no ambiguity — it knows precisely which file you mean, out of the hundreds of thousands on your computer. A path is an address, and an address is how you hand someone the one thing you mean.

What’s next

Paths point at files. But what kind of file is at the end of the path? That’s usually written into the path itself, in the bit after the last dot — the extension. That’s next.