Installing Deno - Visual Walkthrough

Concept Flow - Installing Deno

Start

↓

Check OS

↓

Choose Install Method

↓

Run Install Command

↓

Verify Installation

↓

Done

This flow shows the steps to install Deno: start, check your operating system, pick the right install method, run the command, verify it works, then finish.

Execution Sample

Deno

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

deno --version

This code downloads and runs the Deno install script, then checks the installed version.

Execution Table

Step	Action	Command Run	Result	Next Step
1	Check OS	uname or system info	Detected OS (Linux/macOS/Windows)	Choose Install Method
2	Choose Install Method	Decide based on OS	Select curl script or PowerShell	Run Install Command
3	Run Install Command	curl -fsSL https://deno.land/install.sh | sh	Deno installed in user directory	Verify Installation
4	Verify Installation	deno --version	Shows Deno version number	Done
5	Done	N/A	Deno ready to use	End

💡 Installation completes after verifying Deno version.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
OS	Unknown	Linux/macOS/Windows	Linux/macOS/Windows	Linux/macOS/Windows	Linux/macOS/Windows	Linux/macOS/Windows
Install Method	None	None	curl script or PowerShell	curl script or PowerShell	curl script or PowerShell	curl script or PowerShell
Deno Installed	No	No	No	Yes	Yes	Yes
Deno Version	None	None	None	None	v1.x.x or later	v1.x.x or later

Key Moments - 3 Insights

Why do I need to check my operating system before installing Deno?

Because the install command differs by OS, as shown in execution_table step 2 where the method is chosen based on OS.

What does the command 'curl -fsSL https://deno.land/install.sh | sh' do?

It downloads the install script and runs it immediately, installing Deno as shown in execution_table step 3.

How do I know if Deno installed correctly?

By running 'deno --version' which should show the version number, as in execution_table step 4.

Visual Quiz - 3 Questions

Look at the execution table, what is the result after running the install command?

A Deno installed in user directory

B Deno version displayed

C Operating system detected

D Installation failed

💡 Hint

Check the 'Result' column in step 3 of the execution table.

At which step does the installation verification happen?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look for the step where 'deno --version' is run in the execution table.

If your OS is Windows, which install method would you likely choose?

A curl script

B PowerShell script

C Manual download only

D No installation needed

💡 Hint

Refer to the 'Choose Install Method' step in the execution table and variable_tracker.

Concept Snapshot

Installing Deno:
1. Check your OS (Linux/macOS/Windows).
2. Choose install method (curl script for Linux/macOS, PowerShell for Windows).
3. Run install command.
4. Verify with 'deno --version'.
5. Deno is ready to use.

Full Transcript

To install Deno, first check your operating system. Then pick the right install method: curl script for Linux or macOS, PowerShell for Windows. Run the install command to download and install Deno. After installation, verify by running 'deno --version' to see the installed version. Once verified, Deno is ready to use.

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