A Guide to Powershell

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 What is Powershell?


PowerShell is a command-line shell and scripting language developed by Microsoft for task automation and configuration management. Built on the .NET Framework, it offers full access to COM and WMI, enabling system administrators to perform administrative tasks on both local and remote Windows systems. It includes a command-line shell, an associated scripting language, and a framework for processing cmdlets. PowerShell commands, called "cmdlets", enable managing the computers from the command line. PowerShell providers allow access to data stores, such as the registry and certificate store, as easily as you access the file system.

PowerShell enables IT professionals and developers to control and automate the administration of Windows and applications. It is object-oriented and gives access to a host of information, including system components (filesystem, registry), services, processes, events, and more. PowerShell certification course also supports remote management, allowing admins to work on many systems simultaneously from a single machine. It has a robust security model and supports various standard data streams for better scripting practices.

PowerShell online training is open-source, ensuring that it can be used across different platforms, including macOS and Linux. It continues to evolve with contributions from the community and is a powerful tool for system administration and automation tasks.

History of Powershell

PowerShell, initially known as Monad, was developed by Microsoft in 2002 to help administrators manage and automate tasks on Windows. Released in 2006 as Windows PowerShell, it integrated with Microsoft's .NET Framework and offered a scripting language and command-line shell. PowerShell was continually enhanced over multiple versions. In 2016, Microsoft open-sourced PowerShell and released PowerShell Core, a cross-platform version compatible with macOS and Linux. As of my knowledge cut-off in 2021, PowerShell 7, the successor to PowerShell Core and Windows PowerShell, continues this cross-platform approach.

PowerShell Versions

The following are the primary versions of PowerShell online training & certification course that have been released:

  1. PowerShell 1.0 - Released in 2006, this was the initial release and was available for Windows XP SP2, Windows Server 2003 SP1, and Windows Vista.
  2. PowerShell 2.0 - Released in 2009, it was included with Windows 7 and Windows Server 2008 R2. It introduced many new features, including remoting, background jobs, the Integrated Scripting Environment (ISE), and advanced functions.
  3. PowerShell 3.0 - Released in 2012 and included with Windows 8 and Windows Server 2012, it introduced the CIM cmdlets and improved workflow support.
  4. PowerShell 4.0 - Released in 2013 and included with Windows 8.1 and Windows Server 2012 R2. It introduced Desired State Configuration (DSC).
  5. PowerShell 5.0 - Released in 2016 as part of the Windows Management Framework 5.0. It added class definitions and other features to the language and introduced PowerShellGet for module management.
  6. PowerShell Core 6.0 - Released in 2018, this version of PowerShell was redesigned to be cross-platform, working on Windows, macOS, and Linux. It was also open-sourced.
  7. PowerShell 7.0 - Released in 2020, this version aimed to bring parity between Windows PowerShell 5.1 and PowerShell Core 6. It replaced PowerShell Core and runs on Windows, macOS, and Linux.

Uses of PowerShell

Following are some uses of Powershell online certification course:

  • Automating repetitive administrative tasks to increase efficiency.
  • Managing Windows servers and other Microsoft technologies remotely.
  • Creating and managing system and user environment variables.
  • Testing network connections and diagnosing network issues.
  • Automating software installs and updates across multiple machines. 

How to launch PowerShell?

There are a few ways to launch PowerShell on a Windows system:

  1. Search: Click the Start button or press the Windows key, then type "PowerShell" into the search box. Click on the "Windows PowerShell" application in the results list.
  2. Run Dialog: Press Windows key + R to open the Run dialog, type "powershell" into the box, and press Enter or click OK.
  3. Command Prompt: Open a Command Prompt window, type "powershell" into the prompt, and press Enter.
  4. PowerShell ISE: The PowerShell Integrated Scripting Environment (ISE) is another way to use PowerShell, providing a GUI-based experience. You can open it similarly to the above methods, just type "PowerShell ISE" instead.

Features of Windows PowerShell

Here is a brief explanation of the Windows PowerShell features:

  1. PowerShell Remoting: Allows for running commands on one or many remote computers from a local PowerShell session, using the WS-Management protocol.
  2. Background Job: Lets you run commands or scripts in the background while you continue to work in the same or another console.
  3. Scheduled Job: Allows you to schedule the execution of PowerShell cmdlets, scripts, and script blocks, similar to how you might use Task Scheduler.
  4. Steppable Pipeline: Allows you to step into a script or function as its running and interact with it step by step.
  5. Script Debugging: Integrated debugging features let you set breakpoints, step through code, and check variable values during script execution.
  6. Eventing: PowerShell can subscribe to and handle events, just like an event-driven programming language. This makes it capable of responding to system events or changes in data.
  7. Error-Handling: Provides powerful options for trapping and handling errors in scripts, including try/catch/finally blocks.
  8. Constrained Runspaces: Allow you to restrict what a user can do in a PowerShell session. You can limit the cmdlets, providers, and scripts that are available.
  9. Tab-Expansion: A feature for automatically completing cmdlet names, variable names, and other inputs when you press the Tab key.
  10. Windows PowerShell Web Access: Enables you to run PowerShell commands and scripts in a web-based console, allowing access from any device with a web browser.
  11. Desired State Configuration (DSC): A feature for declaratively specifying the desired state of a system configuration, allowing for automated, idempotent configuration management.
  12. Network File Transfer: PowerShell provides cmdlets for transferring files over a network, such as ‘Copy-Item’ with a UNC path, or using the BITS transfer cmdlets.

Each of these features significantly enhances the power and versatility of PowerShell as a tool for system administration and automation.

What is the PowerShell ISE?

PowerShell Integrated Scripting Environment (ISE) is a hosting application for Windows PowerShell. It provides a graphical interface to write, test, and debug scripts, making it easier to develop complex PowerShell commands and scripts. ISE includes features like syntax-coloring, tab completion, context-sensitive help, and support for multiple PowerShell tabs, each with its own execution environment.

What is PowerShell Cmdlet?

A PowerShell cmdlet (pronounced "command-let") is a lightweight command used in the PowerShell environment. It's built on .NET Framework and is designed to perform a specific function or task. Cmdlets follow a Verb-Noun syntax, such as Get-Process, where 'Get' is the verb, indicating the action, and 'Process' is the noun, indicating the entity to act upon. Unlike shell commands, cmdlets return .NET objects, which means they can be directly processed, allowing you to pipeline multiple cmdlets together for complex tasks.

Cmdlet Format

In PowerShell, cmdlets follow a Verb-Noun naming convention, where the Verb represents the action the cmdlet performs, and the Noun represents the resource on which the action is performed. Here are explanations for the verbs you've listed:

  1. Get: Retrieves data. For example, ‘Get-Process’ retrieves information about the running processes.
  2. Set: Modifies existing resources. For example, ‘Set-Service’ modifies the status of a service in the service control manager.
  3. Start: Initiates a resource or process. For example, ‘Start-Service’ starts a stopped service.
  4. Stop: Ends a process or deactivates a resource. For example, ‘Stop-Process’ stops a running process.
  5. Out: Sends output to a specified location. For example, ‘Out-File’ sends output to a file.
  6. New: Creates a new resource. For example, ‘New-Item’ creates a new item in a namespace (like a new file in a filesystem).

When you use these verbs in a cmdlet, you follow them with a hyphen and then the noun of the resource you want to interact with. For instance, if you want to get information about a service, you would use the cmdlet ‘Get-Service’.

Cmdlet vs. Command

Both cmdlets and commands are used to perform tasks in a shell environment, but they are different in terms of their structure, functionality, and the way they handle and return data.

Cmdlet: Cmdlets (pronounced "command-lets") are the built-in commands in PowerShell. They are instances of .NET classes and not standalone executables. Cmdlets have a Verb-Noun naming convention, such as Get-Process, and are designed to work with objects. They receive objects from the pipeline, process them, and typically return .NET objects. This makes it easy to pass data from one cmdlet to another, allowing for a powerful, streamlined data processing pipeline.

Command: A command typically refers to an executable program in the operating system that performs a specific task, like ‘ipconfig’ or ‘ping’ in Windows. Commands can be run in various shell environments, including PowerShell, but they don't have the same Verb-Noun naming structure as cmdlets. They're standalone programs that don't directly work with .NET objects or the PowerShell pipeline. When you run a command in PowerShell, it's often because there's no built-in cmdlet that performs the same task, or because you're invoking a command-line tool that has its own syntax and functionality.

PowerShell vs. CMD (Command Prompt)

PowerShell and Command Prompt (CMD) are both command-line interfaces (CLIs) in the Windows environment, but they have key differences in terms of power, flexibility, and functionality:

  1. Scripting Language: PowerShell is built on the .NET framework and uses a scripting language that's capable of performing complex operations. CMD uses a simpler batch scripting language that's less powerful and flexible.
  2. Cmdlets vs. Commands: PowerShell uses cmdlets (command-lets), which are built-in commands in PowerShell that are instances of .NET classes. Cmdlets work with objects, allowing for a more streamlined and powerful data processing pipeline. CMD uses commands, which are standalone executables that do not directly work with .NET objects.
  3. Object-Oriented: PowerShell is object-oriented, meaning its cmdlets output .NET objects. This allows for more complex and efficient data manipulation. CMD is not object-oriented, and its output is simply text.
  4. Pipelines: PowerShell's pipelines allow for passing of full objects with their properties and methods from one cmdlet to another. CMD can pass only text from one command to the next.
  5. Versatility: PowerShell can interact with a wide range of technologies including Windows Management Instrumentation (WMI), Component Object Model (COM) objects, and .NET classes, offering administrators extensive control over the system. CMD does not have this level of versatility.

PowerShell Scripts

PowerShell scripts are files that contain a series of PowerShell commands or cmdlets that perform a particular task. They are useful for automating repetitive tasks and performing complex operations. PowerShell scripts are saved with a ‘.ps1’ extension.

Scripting in PowerShell allows for advanced functions, error handling, parameterized inputs, and many other programming features, making it a powerful tool for automating administrative tasks.

PowerShell Loops

Loops in PowerShell are used to repeatedly execute a block of statements until a certain condition is met. There are several types of loops you can use in PowerShell:

  1. For Loop: A For loop is used when you want to run a command or set of commands a set number of times.
  2. ForEach Loop: A ForEach loop is used to iterate through each item in a collection or array.
  3. While Loop: A While loop will continue to run as long as the condition specified is true.

Types of PowerShell Variables

In PowerShell, variables store values that can be used and manipulated within scripts and commands. There are different types of variables in PowerShell:

  1. User-created Variables: These are the variables that you create in your PowerShell session or script. You can assign any value to these variables including strings, integers, arrays, and even objects. Once you create a variable, it remains in memory until you close the session or manually remove it using the Remove-Variable cmdlet.
  2. Automatic Variables: These are predefined variables in PowerShell and are created and maintained by PowerShell itself. They store state information for PowerShell. These include variables like ‘$?’ (Contains the execution status of the last command), ‘$$’ (contains the last token in the last line received by the session), ‘$^’ (contains the first token in the last line received by the session), and ‘$_’ (contains the current object in the pipeline).
  3. Preference Variables: These are also predefined variables in PowerShell and are used to customize the behavior of PowerShell for the user. For example, $ErrorActionPreference determines how PowerShell responds to non-terminating errors from commands. Other preference variables include ‘$DebugPreference’, ‘$WarningPreference’, ‘$VerbosePreference’, and more.

Conclusion

As we conclude this comprehensive guide on PowerShell online training course by Multisoft Virtual Academy, it is evident that PowerShell is an incredibly robust and flexible task automation and configuration management framework. It provides numerous advantages over traditional command line interfaces, such as object-oriented scripting language, ease of use, wide applicability, and extensive access to system-level functionalities. PowerShell certification course is indeed a critical skill for IT professionals and developers who are interested in automating and managing the Windows ecosystem. Multisoft Virtual Academy is committed to helping you explore more of these powerful tools and technologies that elevate your skills and career to the next level.

We hope you found this guide useful and look forward to assisting you in your future learning endeavors.

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