Variable creation with $ in PowerShell - Mini Project: Build & Apply

Variable creation with $ in PowerShell

📖 Scenario: You are writing a simple PowerShell script to store and display information about a fruit.

🎯 Goal: Learn how to create and use variables in PowerShell using the $ symbol.

📋 What You'll Learn

Create a variable with the exact name $fruit

Assign the exact value Apple to $fruit

Create a variable with the exact name $quantity

Assign the exact value 10 to $quantity

Use a variable $message to combine $fruit and $quantity in a string

Print the $message variable

💡 Why This Matters

🌍 Real World

Variables are used in scripts to store data like names, counts, or settings. This helps automate tasks by reusing values easily.

💼 Career

Knowing how to create and use variables is essential for writing PowerShell scripts in IT jobs, system administration, and automation.

1

Create a variable called $fruit

Create a variable called $fruit and assign it the value Apple.

PowerShell

# Create a variable called $fruit and assign it the value 'Apple'
# Your code here

Hint

Use the $ symbol before the variable name and assign the string value with single quotes.

2

Create a variable called $quantity

Create a variable called $quantity and assign it the value 10.

PowerShell

$fruit = 'Apple'
# Create a variable called $quantity and assign it the value 10
# Your code here

Hint

Remember to use $ before the variable name and assign the number without quotes.

3

Combine variables into $message

Create a variable called $message that combines $quantity and $fruit into the string: 10 Apples. Use double quotes and variable expansion.

PowerShell

$fruit = 'Apple'
$quantity = 10
# Create a variable $message combining $quantity and $fruit with an 's' at the end
# Your code here

Hint

Use double quotes and ${fruit}s to add the 's' after the fruit name.

4

Print the $message variable

Print the value of the variable $message using Write-Output.

PowerShell

$fruit = 'Apple'
$quantity = 10
$message = "$quantity ${fruit}s"
# Print the $message variable
# Your code here

Hint

Use Write-Output $message to display the message.

Practice

1. What does the $ symbol do in PowerShell when placed before a word like $name?

easy

A. It prints the word 'name' to the screen.

B. It creates a variable named 'name' to store data.

C. It comments out the line.

D. It runs a command called 'name'.

Solution

1. Step 1: Understand the role of $ in PowerShell

   The $ symbol is used to declare or access variables in PowerShell.

2. Step 2: Identify what $name means

   $name means a variable named 'name' that can hold data like text or numbers.

3. Final Answer:

   It creates a variable named 'name' to store data. -> Option B

4. Quick Check:

   $ before word = variable creation [OK]

Hint: Remember: $ always starts a variable name [OK]

Common Mistakes:

• Thinking $ runs commands
• Confusing $ with comments
• Assuming $ prints text directly

2. Which of the following is the correct way to create a variable named age with the value 30 in PowerShell?

easy

A. $age = 30

B. set age = 30

C. age = 30

D. var $age = 30

Solution

1. Step 1: Recall PowerShell variable syntax

   Variables start with $ and assignment uses =.

2. Step 2: Check each option

   $age = 30 uses $age = 30, which is correct syntax for variable creation and assignment.

3. Final Answer:

   $age = 30 -> Option A

4. Quick Check:

   Variable = $name = value [OK]

Hint: Always start variable names with $ in PowerShell [OK]

Common Mistakes:

• Omitting the $ before variable name
• Using 'set' keyword which is not PowerShell syntax
• Adding 'var' keyword which is not used in PowerShell

3. What will be the output of this PowerShell code?

$greeting = "Hello"
$name = "Sam"
Write-Output "$greeting, $name!"

medium

A. Error: Variable not defined

B. $greeting, $name!

C. Hello $name!

D. Hello, Sam!

Solution

1. Step 1: Understand variable assignment

   $greeting is assigned "Hello" and $name is assigned "Sam".

2. Step 2: Understand string interpolation in double quotes

   Inside double quotes, variables like $greeting and $name are replaced by their values.

3. Final Answer:

   Hello, Sam! -> Option D

4. Quick Check:

   Variables inside "" show their values [OK]

Hint: Use double quotes to insert variables inside strings [OK]

Common Mistakes:

• Using single quotes which do not expand variables
• Expecting variable names to print literally
• Forgetting to assign variables before use

4. Identify the error in this PowerShell script:

$number = 10
$number = $number + 5
Write-Output number

medium

A. Cannot add numbers in PowerShell

B. Variable $number not declared

C. Missing $ before 'number' in Write-Output

D. Write-Output cannot print variables

Solution

1. Step 1: Check variable usage in Write-Output

   The script tries to print 'number' without $, so it prints the word literally.

2. Step 2: Correct usage of variable in output

   To print the variable value, it should be Write-Output $number.

3. Final Answer:

   Missing $ before 'number' in Write-Output -> Option C

4. Quick Check:

   Variables need $ to be recognized [OK]

Hint: Always use $ before variable names when printing [OK]

Common Mistakes:

• Forgetting $ before variable in output
• Thinking variables need declaration keyword
• Assuming Write-Output can't print variables

5. You want to create a variable $fullName by combining two variables $firstName and $lastName with a space in between. Which code correctly does this in PowerShell?

hard

A. $fullName = $firstName + " " + $lastName

B. $fullName = '$firstName $lastName'

C. $fullName = $firstName $lastName

D. $fullName = "$firstName$lastName"

Solution

1. Step 1: Understand string concatenation in PowerShell

   Use + to join strings and include a space as " ".

2. Step 2: Analyze each option

   $fullName = $firstName + " " + $lastName correctly adds $firstName, a space, and $lastName to form full name.

3. Final Answer:

   $fullName = $firstName + " " + $lastName -> Option A

4. Quick Check:

   Use + and " " to join variables with space [OK]

Hint: Use + and " " to join variables with space [OK]

Common Mistakes:

• Using single quotes which do not expand variables
• Missing operator between variables
• Concatenating without space when needed