PowerShell on Linux - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is PowerShell on Linux?

PowerShell on Linux is a cross-platform command-line shell and scripting language that works on Linux, macOS, and Windows. It lets you automate tasks and manage systems using the same commands and scripts across different operating systems.

beginner

How do you install PowerShell on a Linux system like Ubuntu?

You can install PowerShell on Ubuntu by running these commands:

sudo apt update
sudo apt install -y wget apt-transport-https software-properties-common
wget -q https://packages.microsoft.com/config/ubuntu/22.04/packages-microsoft-prod.deb
sudo dpkg -i packages-microsoft-prod.deb
sudo apt update
sudo apt install -y powershell

Then start PowerShell by typing pwsh.

beginner

How do you start PowerShell on Linux after installation?

Open your terminal and type pwsh then press Enter. This launches the PowerShell shell where you can run PowerShell commands and scripts.

intermediate

Can PowerShell scripts written on Windows run on Linux without changes?

Most PowerShell scripts run on Linux without changes because PowerShell is cross-platform. However, scripts that use Windows-specific features like Windows Registry or Windows-only cmdlets may need adjustments.

beginner

What is a simple PowerShell command to list files in the current directory on Linux?

Use Get-ChildItem or its alias ls to list files and folders in the current directory. For example:

Get-ChildItem

This works similarly on Linux and Windows.

Which command starts PowerShell on a Linux terminal?

A bash

B powershell.exe

C pwsh

D sh

On Linux, PowerShell is started by typing 'pwsh' in the terminal.

What package manager command is used to install PowerShell on Ubuntu?

A apt install powershell

B yum install powershell

C pacman -S powershell

D dnf install powershell

Ubuntu uses 'apt' as its package manager, so 'apt install powershell' installs PowerShell.

Which of these is a PowerShell cmdlet to list directory contents?

A ls -l

B Get-ChildItem

C dir /w

D cat

'Get-ChildItem' is the PowerShell cmdlet to list files and folders.

True or False: PowerShell on Linux supports Windows Registry commands.

A False

B Only with special modules

C Only on Ubuntu

D True

Windows Registry is a Windows-only feature and is not supported on Linux PowerShell.

What is the main benefit of PowerShell being cross-platform?

A It replaces Bash on Linux.

B It runs faster on Linux than Windows.

C It only works on Linux servers.

D You can use the same scripts on Windows, Linux, and macOS.

Cross-platform means you can run the same PowerShell scripts on different operating systems.

Explain how to install and start PowerShell on a Linux system.

Think about the commands you run in the terminal step by step.

Describe the advantages and limitations of using PowerShell on Linux compared to Windows.

Consider what works the same and what might be different.

Practice

1. What command do you use to start PowerShell on a Linux system?

easy

A. pwsh

B. powershell.exe

C. start-ps

D. shellps

Solution

1. Step 1: Recall the PowerShell start command on Linux

   On Linux, PowerShell is started by typing pwsh in the terminal.

2. Step 2: Compare options with the known command

   powershell.exe, start-ps, and shellps are not valid commands to start PowerShell on Linux.

3. Final Answer:

   pwsh -> Option A

4. Quick Check:

   PowerShell start command on Linux = pwsh [OK]

Hint: Remember: 'pwsh' starts PowerShell on Linux terminals [OK]

Common Mistakes:

• Typing 'powershell.exe' which is for Windows only
• Using 'start-ps' which is not a valid command
• Confusing shell names

2. Which of the following is the correct syntax to run a Linux command inside PowerShell on Linux?

easy

A. Run-Command 'ls -l'

B. Invoke-Linux ls -l

C. ls -l

D. Start-Linux ls -l

Solution

1. Step 1: Understand how Linux commands run in PowerShell on Linux

   PowerShell on Linux allows running Linux commands directly by typing them as is, like ls -l.

2. Step 2: Evaluate each option

   Invoke-Linux ls -l, Run-Command 'ls -l', and Start-Linux ls -l are not valid syntax to run Linux commands.

3. Final Answer:

   ls -l -> Option C

4. Quick Check:

   Run Linux commands directly in PowerShell = ls -l [OK]

Hint: Run Linux commands directly without extra syntax in PowerShell [OK]

Common Mistakes:

• Adding unnecessary PowerShell cmdlets before Linux commands
• Using quotes incorrectly around Linux commands
• Assuming Linux commands need special wrappers

3. What will be the output of this PowerShell on Linux command sequence?

pwsh
$files = ls /etc | Where-Object { $_.Name -like '*.conf' }
$files.Count

medium

A. Always zero because filtering is incorrect

B. An error because ls is not recognized

C. The list of all files in /etc

D. The number of files in /etc ending with .conf

Solution

1. Step 1: Understand the command sequence

   The command ls /etc lists files in /etc. The Where-Object filters files whose names end with '.conf'.

2. Step 2: Determine the output of $files.Count

   $files stores the filtered list, so $files.Count returns the number of such files.

3. Final Answer:

   The number of files in /etc ending with .conf -> Option D

4. Quick Check:

   Count filtered files = number [OK]

Hint: Count filtered files with .Count property after Where-Object [OK]

Common Mistakes:

• Thinking ls is not recognized in PowerShell on Linux
• Assuming filtering syntax is invalid
• Confusing output with file list instead of count

4. You run this script in PowerShell on Linux:

pwsh
$process = Get-Process -Name "bash"
Write-Output $process.Id

But it returns an error: "Get-Process: The term 'Get-Process' is not recognized." What is the likely cause?

medium

A. PowerShell is not installed correctly on Linux

B. You are running the script in the Linux shell, not inside PowerShell

C. The process 'bash' does not exist

D. Get-Process cmdlet is not available on Linux PowerShell

Solution

1. Step 1: Analyze the error message

   The error says 'Get-Process' is not recognized, which usually means the command is run outside PowerShell.

2. Step 2: Understand environment context

   If you run PowerShell commands in the Linux shell (bash), they won't work. You must be inside PowerShell (started with pwsh) to run Get-Process.

3. Final Answer:

   You are running the script in the Linux shell, not inside PowerShell -> Option B

4. Quick Check:

   Run PowerShell cmdlets inside pwsh shell [OK]

Hint: Run PowerShell commands only inside pwsh shell, not bash [OK]

Common Mistakes:

• Assuming Get-Process is missing on Linux PowerShell
• Thinking the process 'bash' does not exist
• Not starting PowerShell before running commands

5. You want to write a PowerShell script on Linux that lists all running processes and filters only those owned by the current user. Which approach is correct?

hard

A. Get-Process | Where-Object { $_.UserName -eq $env:USER }

B. ps -u $USER | pwsh

C. Get-Process | Where-Object { $_.UserName -eq (whoami) }

D. Get-Process | Where-Object { $_.UserName -eq $env:USERNAME }

Solution

1. Step 1: Identify environment variable for current user in PowerShell on Linux

   PowerShell on Linux uses $env:USER to get the current user's name.

2. Step 2: Check filtering syntax for processes

   Filtering processes by Where-Object { $_.UserName -eq $env:USER } correctly compares the process owner to the current user.

3. Step 3: Evaluate other options

   ps -u $USER | pwsh mixes Linux command with PowerShell incorrectly. Get-Process | Where-Object { $_.UserName -eq (whoami) } uses command output that may not match precisely. Get-Process | Where-Object { $_.UserName -eq $env:USERNAME } uses $env:USERNAME which is typically not set on Linux.

4. Final Answer:

   Get-Process | Where-Object { $_.UserName -eq $env:USER } -> Option A

5. Quick Check:

   Use $env:USER for current user in PowerShell on Linux [OK]

Hint: Use $env:USER to get current user in PowerShell on Linux [OK]

Common Mistakes:

• Using $env:USERNAME which isn't set on Linux PowerShell
• Mixing Linux commands like 'ps -u $USER' with PowerShell incorrectly
• Using command output like (whoami) without precise matching