Environment variables in PowerShell - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an environment variable in PowerShell?

An environment variable is a named value stored by the operating system that programs can use to get information like paths or settings. In PowerShell, you can access them to customize scripts or system behavior.

beginner

How do you list all environment variables in PowerShell?

Use the command Get-ChildItem Env: or its alias gci Env: to see all environment variables and their values.

beginner

How can you read the value of an environment variable named 'PATH' in PowerShell?

Use $Env:PATH to get the value of the PATH environment variable.

beginner

How do you set or change an environment variable in PowerShell for the current session?

Assign a new value like $Env:MYVAR = 'Hello'. This change lasts only while the PowerShell window is open.

beginner

What happens if you set an environment variable in PowerShell and then close the window?

The environment variable change is lost because it was only set for the current session. To keep it permanently, you must set it in system settings or the registry.

Which PowerShell command lists all environment variables?

A Get-Process

B Get-ChildItem Env:

C Get-Content Env:

D Set-Variable Env:

Get-ChildItem Env: lists all environment variables and their values.

How do you access the value of the environment variable 'USERNAME' in PowerShell?

A $Env:USERNAME

B $Env.USERNAME

C Get-Env USERNAME

D Read-Env USERNAME

Use $Env:USERNAME to access the value of the USERNAME environment variable.

If you set $Env:MYVAR = 'Test' in PowerShell, when does this change disappear?

A Never, it is permanent

B Immediately after setting

C When you close the PowerShell window

D After restarting the computer

Changes to environment variables in PowerShell last only for the current session and disappear when the window closes.

Which prefix is used to access environment variables in PowerShell?

A $Env:

B $Env.

C $Env-

D $Env_

Environment variables are accessed with the $Env: prefix in PowerShell.

To permanently set an environment variable in Windows, you should:

A Run Get-ChildItem Env:

B Use $Env:VAR = 'value' in PowerShell

C Restart PowerShell

D Set it in system settings or registry

Permanent environment variables must be set in system settings or the Windows registry, not just in PowerShell.

Explain how to view, read, and set environment variables in PowerShell.

Think about commands to list, read, and assign environment variables.

Describe the difference between temporary and permanent environment variables in Windows and PowerShell.

Consider where variables are stored and how long they last.

Practice

1. What is the correct way to access the environment variable PATH in PowerShell?

easy

A. Use PATH$

B. Use get-env PATH

C. Use env(PATH)

D. Use $env:PATH

Solution

1. Step 1: Understand PowerShell environment variable syntax

   PowerShell uses $env:VARIABLE_NAME to access environment variables.

2. Step 2: Apply syntax to PATH variable

   To get the PATH variable, write $env:PATH.

3. Final Answer:

   Use $env:PATH -> Option D

4. Quick Check:

   Environment variable access = $env:VARIABLE [OK]

Hint: Remember: environment variables use $env: prefix in PowerShell [OK]

Common Mistakes:

• Using incorrect syntax like get-env or env()
• Forgetting the $env: prefix
• Trying to access variables without colon

2. Which of the following is the correct syntax to set an environment variable named MY_VAR to the value hello in PowerShell?

easy

A. set-env MY_VAR hello

B. $env:MY_VAR = 'hello'

C. env MY_VAR = hello

D. set $env:MY_VAR hello

Solution

1. Step 1: Recall how to assign environment variables in PowerShell

   PowerShell assigns environment variables by setting $env:VariableName to a value.

2. Step 2: Apply assignment to MY_VAR

   Use $env:MY_VAR = 'hello' to set the variable.

3. Final Answer:

   $env:MY_VAR = 'hello' -> Option B

4. Quick Check:

   Set env var = $env:VAR = value [OK]

Hint: Set env vars with $env:VAR = 'value' syntax [OK]

Common Mistakes:

• Using set-env which is not a PowerShell cmdlet
• Missing quotes around string values
• Trying to assign without $env: prefix

3. What will be the output of the following PowerShell commands?

$env:GREETING = 'Hello'
Write-Output "$env:GREETING, World!"

medium

A. Hello, World!

B. $env:GREETING, World!

C. GREETING, World!

D. Error: Variable not found

Solution

1. Step 1: Assign environment variable GREETING

   The command $env:GREETING = 'Hello' sets the environment variable GREETING to 'Hello'.

2. Step 2: Output the string with variable expansion

   The command Write-Output "$env:GREETING, World!" expands $env:GREETING to 'Hello', so the output is 'Hello, World!'.

3. Final Answer:

   Hello, World! -> Option A

4. Quick Check:

   Variable expands correctly = Hello, World! [OK]

Hint: Variables inside double quotes expand automatically in PowerShell [OK]

Common Mistakes:

• Expecting literal $env:GREETING instead of expansion
• Using single quotes which prevent expansion
• Assuming environment variables are not accessible in strings

4. You run this script but get an error:

Write-Output $envMY_VAR

What is the error and how to fix it?

medium

A. Environment variables cannot be used in Write-Output

B. Variable name is case sensitive; use $env:my_var

C. Missing colon after env; fix by using $env:MY_VAR

D. Use double quotes around variable: "$envMY_VAR"

Solution

1. Step 1: Identify syntax error in variable name

   The variable $envMY_VAR is invalid because environment variables require a colon after env, like $env:MY_VAR.

2. Step 2: Correct the syntax

   Fix the script by changing to Write-Output $env:MY_VAR to properly access the environment variable.

3. Final Answer:

   Missing colon after env; fix by using $env:MY_VAR -> Option C

4. Quick Check:

   Env vars need colon after env = $env:VAR [OK]

Hint: Always use colon after env to access variables: $env:VAR [OK]

Common Mistakes:

• Omitting colon after env
• Assuming variable names are case sensitive
• Trying to quote variable name instead of fixing syntax

5. You want to temporarily add a folder C:\Tools to the PATH environment variable for your current PowerShell session only. Which command correctly does this?

hard

A. $env:PATH = $env:PATH + ';C:\Tools'

B. setx PATH "$env:PATH;C:\Tools"

C. New-Item -Path Env:PATH -Value 'C:\Tools'

D. $env:PATH += 'C:\Tools'

Solution

1. Step 1: Understand session vs persistent environment variables

   Modifying $env:PATH directly changes it only for the current session.

2. Step 2: Append new folder to existing PATH

   Use $env:PATH = $env:PATH + ';C:\Tools' to add the folder, separating with a semicolon.

3. Final Answer:

   $env:PATH = $env:PATH + ';C:\Tools' -> Option A

4. Quick Check:

   Append with $env:PATH = $env:PATH + ';new_path' [OK]

Hint: Append with $env:PATH = $env:PATH + ';new_folder' for session only [OK]

Common Mistakes:

• Using setx which changes persistent variables, not session
• Using += without semicolon separator
• Overwriting PATH without appending