Book Image

Mastering Windows PowerShell Scripting (Second Edition) - Second Edition

By : Brenton J.W. Blawat
Book Image

Mastering Windows PowerShell Scripting (Second Edition) - Second Edition

By: Brenton J.W. Blawat

Overview of this book

PowerShell scripts offer a handy way to automate various chores. Working with these scripts effectively can be a difficult task. This comprehensive guide starts from scratch and covers advanced-level topics to make you a PowerShell expert. The first module, PowerShell Fundamentals, begins with new features, installing PowerShell on Linux, working with parameters and objects, and also how you can work with .NET classes from within PowerShell. In the next module, you’ll see how to efficiently manage large amounts of data and interact with other services using PowerShell. You’ll be able to make the most of PowerShell’s powerful automation feature, where you will have different methods to parse and manipulate data, regular expressions, and WMI. After automation, you will enter the Extending PowerShell module, which covers topics such as asynchronous processing and, creating modules. The final step is to secure your PowerShell, so you will land in the last module, Securing and Debugging PowerShell, which covers PowerShell execution policies, error handling techniques, and testing. By the end of the book, you will be an expert in using the PowerShell language.
Table of Contents (24 chapters)
Title Page
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Enumerating and filtering


Enumerating, or listing, the objects in a collection in PowerShell does not need a specialized command. For example, if the results of Get-PSDrive were assigned to a variable, enumerating the content of the variable is as simple as writing the variable name and pressing Return:

PS> $drives = Get-PSDrive
$drives
Name     Used (GB) Free (GB) Provider   Root
----     --------- --------- --------   ----
Alias                        Alias 
C           319.37   611.60  FileSystem  C:\
Cert                         Certificate \ 
Env                          Environment 
...

ForEach-Object may be used where something complex needs to be done to each object.

Where-Object may be used to filter results.

The ForEach-Object command

ForEach-Object is most often used as a loop (of sorts). For example, the following command works on each of the results from Get-Process in turn:

Get-Process | ForEach-Object { 
    Write-Host $_.Name -ForegroundColor Green 
}

In the preceding example...