Installing Deno - Try It Yourself

Installing Deno

📖 Scenario: You want to start using Deno, a modern runtime for JavaScript and TypeScript. To do this, you need to install Deno on your computer so you can run Deno programs.

🎯 Goal: Learn how to install Deno on your system using the official installation command.

📋 What You'll Learn

Use the official Deno installation command

Verify the installation by checking the Deno version

Use the terminal or command prompt for installation

Follow step-by-step instructions to complete installation

💡 Why This Matters

🌍 Real World

Installing Deno is the first step to running modern JavaScript and TypeScript programs outside the browser, useful for building servers, tools, and scripts.

💼 Career

Knowing how to install and set up Deno is important for developers working with modern JavaScript runtimes and server-side development.

1

Open your terminal or command prompt

Open your terminal (Mac/Linux) or command prompt (Windows) to prepare for installing Deno.

Deno

# Open your terminal or command prompt
# Your code here

Hint

Use your computer's terminal or command prompt application.

2

Run the Deno installation command

Type the exact command curl -fsSL https://deno.land/install.sh | sh in your terminal or command prompt and press Enter to start installing Deno.

Deno

# Open your terminal or command prompt
curl -fsSL https://deno.land/install.sh | sh  # Your code here

Hint

This command downloads and runs the official Deno install script.

3

Add Deno to your system PATH

Add Deno to your system PATH by running export DENO_INSTALL="$HOME/.deno" and export PATH="$DENO_INSTALL/bin:$PATH" in your terminal.

Deno

# Open your terminal or command prompt
curl -fsSL https://deno.land/install.sh | sh
export DENO_INSTALL="$HOME/.deno"
export PATH="$DENO_INSTALL/bin:$PATH"  # Your code here

Hint

This step makes sure your system can find the Deno program.

4

Verify Deno installation

Type deno --version in your terminal and press Enter to check that Deno installed correctly and see its version.

Deno

# Open your terminal or command prompt
curl -fsSL https://deno.land/install.sh | sh
export DENO_INSTALL="$HOME/.deno"
export PATH="$DENO_INSTALL/bin:$PATH"
deno --version  # Your code here

Hint

This command shows the installed Deno version if installation was successful.

Practice

1. What is the main command to check if Deno is installed correctly on your system?

easy

A. deno --version

B. deno install

C. deno start

D. deno run

Solution

1. Step 1: Understand the purpose of the command

   The command deno --version is used to check the installed version of Deno, confirming installation.

2. Step 2: Compare with other commands

   Other commands like deno install, deno start, and deno run are for running or installing scripts, not checking installation.

3. Final Answer:

   deno --version -> Option A

4. Quick Check:

   Check installation = deno --version [OK]

Hint: Use 'deno --version' to verify installation quickly [OK]

Common Mistakes:

• Trying to use 'deno install' to check installation
• Confusing 'deno run' with installation check
• Using 'deno start' which is not a valid command

2. Which of the following is the correct command to install Deno on Unix-like systems using the terminal?

easy

A. npm install -g deno

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

C. deno install https://deno.land/install.sh

D. wget https://deno.land/install.sh

Solution

1. Step 1: Identify the official installation method

   The official way to install Deno on Unix-like systems is to run the shell script via curl piped to sh.

2. Step 2: Evaluate other options

   npm install -g deno uses npm which is not used for Deno installation. deno install https://deno.land/install.sh is incorrect syntax. wget https://deno.land/install.sh downloads the script but does not execute it.

3. Final Answer:

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

4. Quick Check:

   Unix install = curl script | sh [OK]

Hint: Use curl with pipe to sh for Unix Deno install [OK]

Common Mistakes:

• Trying to install Deno with npm
• Downloading script without executing it
• Using incorrect command syntax

3. After running the installation script on Windows PowerShell, which command will show the installed Deno version if installation succeeded?

medium

A. deno --version

B. deno version

C. deno -v

D. deno check

Solution

1. Step 1: Recall the standard version check command

   The command deno --version is the official way to display the installed version.

2. Step 2: Understand why others are incorrect

   deno version and deno -v are not recognized commands. deno check checks code, not version.

3. Final Answer:

   deno --version -> Option A

4. Quick Check:

   Version command = deno --version [OK]

Hint: Use 'deno --version' to confirm installation on any OS [OK]

Common Mistakes:

• Using 'deno version' instead of 'deno --version'
• Trying 'deno -v' which is invalid
• Confusing 'deno check' with version command

4. You ran curl -fsSL https://deno.land/install.sh | sh on Linux but get a 'command not found' error for deno. What is the most likely cause?

medium

A. Deno is not supported on Linux

B. You need to restart your computer before using Deno

C. You must run the command as root user

D. The installation script did not add Deno to your PATH environment variable

Solution

1. Step 1: Understand the error meaning

   'command not found' means the shell cannot find the deno executable in the PATH.

2. Step 2: Identify common installation issue

   The script installs Deno but may not update PATH automatically, so the shell can't find it until PATH is updated.

3. Final Answer:

   The installation script did not add Deno to your PATH environment variable -> Option D

4. Quick Check:

   Command not found = PATH missing Deno [OK]

Hint: Check if Deno is in PATH after install to fix 'command not found' [OK]

Common Mistakes:

• Assuming a reboot is needed
• Thinking root user is required
• Believing Deno doesn't support Linux

5. You want to install Deno on macOS and ensure it is immediately available in your terminal. Which sequence of commands should you run?

hard

A. curl https://deno.land/install.sh | bash && reboot

B. brew install deno && source ~/.bash_profile

C. curl -fsSL https://deno.land/install.sh | sh && export PATH="$HOME/.deno/bin:$PATH"

D. npm install -g deno && deno --version

Solution

1. Step 1: Identify the official install method for macOS

   Running the curl script piped to sh installs Deno. Then updating PATH with export makes it available immediately.

2. Step 2: Evaluate other options

   brew install deno && source ~/.bash_profile uses Homebrew which is valid but requires shell reload; curl https://deno.land/install.sh | bash && reboot uses bash and reboot unnecessarily; npm install -g deno && deno --version uses npm which is incorrect for Deno.

3. Final Answer:

   curl -fsSL https://deno.land/install.sh | sh && export PATH="$HOME/.deno/bin:$PATH" -> Option C

4. Quick Check:

   Install + update PATH = curl -fsSL https://deno.land/install.sh | sh && export PATH="$HOME/.deno/bin:$PATH" [OK]

Hint: Install with curl script then export PATH to use Deno immediately [OK]

Common Mistakes:

• Using npm to install Deno
• Forgetting to update PATH after install
• Rebooting unnecessarily