Determining Your Version of PowerShell

How to do that

• On your Windows OS, click on the start menu button, and type PowerShell.
• After you find it, right click and Run as administrator.
• PowerShell is not like other command line interfaces or CLIs.
• To determine the version, you have to run the following command: $psversiontable.psversion
• After running the command, you should see tables breaking down the version.

Upgrading to PowerShell 5.1

• Lets say that you have a different version of PS and you want to get the latest one (5.1). This how to guide will help you install the Windows Management Framework 5.1 along with PowerShell 5.1.
• On the Windows OS, go to the browser and search for WMF 5.1 and click on the very first link (should be a download link).
  • Its important that before you download and install it, make sure your system meets the requirements (click on the system requirements tab).
• after downloading the WMF 5.1, open it to run the program, and then it will upgrade.

What's New with PowerShell?

• Various new features extending PS's capability.
• Control and provision complex Windows-based environments
• Backwards compatible:
  • All processes from previous versions should perform without changes
• Classes
  • Similar syntax as object oriented language structure
  • Class and Enum along with other keywords have been added
• Write-Host cmdlet:
  • Defines how PS handles informational stream for data
  • Wrapper for Write-information
  • computable with workloads.

Provisions

• OneGet
  • New module provisions the ability of installing packages from Chocolatey repo
• Chocolate
  • Package Manager for Windows
  • Goal is to provide a framework for installing applications and tools for Windows
• Uses PowerShell to provision NuGet packages
• Benefits of OneGet:
  • List and manage software repositories for compatible packages
  • Install and uninstall packages from repositories.

Benefits of 5.0 Framework

• Package Management cmdlets
• Network Switch cmdlets
• Provides updates for Windows PowerShell and PowerShell ISE, including:
  • Desired State Configuration (DSC)
  • Windows Remote Management (WinRM)
  • Windows Management Instrumentation (WMI)

PowerShell Best Practices

• Using Proper Data Validation Techniques, this means to validate actions in script to ensure the values being passed are accurate.
• Error Handling:
  • Forecasting errors that may appear and writing code to prevent any additional issues
  • Use of wrapping message in a try catch block to provide the user with a descriptive message regarding the issue.
• Limit the Use of Aliases
  • When creating large scripts, often difficult to track aliases
  • Use full cmdlet name to make it easier to read the code for all users
  • Example:
    • Aliases: ls|?{$_.Name -eq 'John'}|gc
    • Full cmdlet name: Get-ChildItem | Where-Object {$PSItem.Name -eg 'John} | Get-Content
• Frequent Use of Commenting in Large Scripts
  • It gets very easy to lose touch when searching through thousands of lines of code.
  • Create comments in more areas of your script
  • Script header
    • A detailed header can provide useful search to locate specific areas of script
    • Inserting comments into the script body can be useful to document what various parts of the script do.
• Resist Using Write-Host
  • Write-Host is the only cmdlet that writes directly to console instead of a pipeline limiting its functionality.
• Write Proper and Clean Code
  • Messy code can be hard to read; not indenting code can make things very difficult to debug for errors, if poorly formatted.
  • Make heavy use of tabs, spaces, and carriage returns.
• Frequent Use of Write-Verbose and Write-Debug
  • Using quotes for comments only benefits the user reading the code.
  • Using Write-Verbose and Write-Debug can assist the user for debugging.
• Use Single Quotes
  • PowerShell searches for back ticks, escape characters, and escape in double quotes.
  • PowerShell also searches for characters after a string character ($) indicating a value using double quote
  • Using single quotes prevents this from happening
• Use Source Control
  • Using version control will assist in managing previous versions or controlling updates if several occur in a short period of time
  • Assists groups of users who are working on specific scripts at the same time.
• Avoid Using Hungarian Notation
  • In the past when VBScript was heavily used, this was common practice: $strMonitor $intCount
• PowerShell uses a different system and would confuse the common PowerShell developer who is not accustomed to VBScript. Example of PowerShell: ** $Monitorname** $cp_count

What is WMF (Windows Management Framework)?

• Driver and delivery mechanism.
  • Provisioning a consistent interface across various versions of Windows and Windows Server
  • Allows the compatibility of installing updates to versions (up to 2 lower versions) below the current one.
• What's new with 5.0?
  • Functionality updated from WMF 4.0
  • Only available for Windows 7 SP1 and 8.1, Windows Server 2008 R2, 2012, and 2012 R2
• Installation instructions
  • Can be installed via command prompt, Control Panel, or .msu, and many depend on Windows type, version, service packs, and KB updates.