Installing Deno - Quick Revision & Summary

Recall & Review

beginner

What is Deno?

Deno is a modern runtime for JavaScript and TypeScript that is secure, simple, and uses modern features.

beginner

How do you install Deno on Windows using PowerShell?

Run the command: iwr https://deno.land/install.ps1 -UseBasicParsing | iex in PowerShell.

beginner

Which command verifies if Deno is installed correctly?

Run deno --version in your terminal to check the installed version.

beginner

Name one way to install Deno on macOS or Linux.

You can install Deno using the shell command: curl -fsSL https://deno.land/install.sh | sh

beginner

Why is it important to add Deno to your system PATH?

Adding Deno to PATH lets you run the deno command from any terminal window easily.

Which command installs Deno on Windows using PowerShell?

A brew install deno

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

C iwr https://deno.land/install.ps1 -UseBasicParsing | iex

D npm install -g deno

On Windows PowerShell, the installation uses the iwr (Invoke-WebRequest) command with the install.ps1 script.

What command checks if Deno is installed correctly?

A deno check

B deno --version

C deno install

D deno start

The command 'deno --version' shows the installed Deno version, confirming installation.

Which operating systems can use the command: curl -fsSL https://deno.land/install.sh | sh ?

A iOS

B Windows only

C Android

D macOS and Linux

The shell script installation works on macOS and Linux systems.

Why do you add Deno to your system PATH?

A To run Deno commands from any terminal

B To update Deno automatically

C To uninstall Deno

D To open Deno's website

Adding Deno to PATH allows running the 'deno' command anywhere in the terminal.

Which of these is NOT a valid way to install Deno?

A Using npm install -g deno

B Using shell script on macOS/Linux

C Using PowerShell script on Windows

D Using Homebrew on macOS

Deno is not installed via npm; npm is for Node.js packages.

Describe the steps to install Deno on a Windows machine.

Think about the PowerShell command and checking the version.

Explain why adding Deno to your system PATH is important after installation.

Consider how commands work in a terminal.

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