Install Deno and check that it works

17 August 2026

I have lost entire afternoons of my life to programming-language setup: version managers, build tools, configuration files that configure other configuration files. That experience picked this course's runtime for me: Deno reads, validates, and executes the files you'll write, and it installs with one command. Before writing any code, you need it installed and answering from your terminal.

Open a terminal

A terminal is an application where you type written commands to your computer. You'll use it for installation now and for running programs constantly later. It's the other half of your workspace, next to the editor.

Windows: open the Start menu, search for PowerShell, and launch it.
macOS: open Spotlight, search for Terminal, and launch it.
Linux: open your distribution's built-in terminal application.

Install Deno on Windows

Copy this command into PowerShell and press Enter:

irm https://deno.land/install.ps1 | iex

This downloads and runs the official Windows installer. Wait for it to complete, then close and reopen PowerShell so the terminal recognizes the new deno command.

Install Deno on macOS or Linux

Copy this command into your terminal and press Enter:

curl -fsSL https://deno.land/install.sh | sh

This downloads and runs the official shell installer. When it finishes, read any final messages for additional setup instructions, then close and reopen your terminal.

Check the installation

Never trust an installer's word for it. Ask the tool itself:

deno --version

Successful output resembles:

deno 2.x.x
v8 x.x.x
typescript x.x.x

The first line is the one that matters. If it begins with deno and a version number, you're set. (Notice typescript in there too; that's a preview of coming attractions.)

If the command is not found

A message like "command not found" or "deno is not recognized" means the terminal hasn't noticed the new installation yet. This happens to everyone; verify two things:

You closed the terminal after installation and opened a fresh one.
The installer's final messages didn't ask for an extra setup step you skipped.

Retry deno --version. If it still won't answer, the official Deno installation guide has a section on typical installation paths under "If you see command not found."

Your setup check

Open a fresh terminal and run:

deno --version

You're ready when the terminal displays a line starting with deno followed by a version number.

No programs yet. Deno is installed, but you need a place to keep course files, and before that, something to write them with.

Installation commands are sourced from the official Deno installation guide.

Next: Install Zed →