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

Character classes


A character class is used to match a single character to a set of possible characters. A character class is denoted using square brackets ([ ]).

For example, a character class may contain each of the vowels:

'get' -match 'g[aeiou]t' 
'got' -match 'g[aeiou]'

Within a character class, the special or reserved characters are as follows:

  • -: Used to define a range
  • \: Escape character
  • ^: Negates the character class

Ranges

The hyphen is used to define a range of characters. For example, we might want to match any number repeated one or more times (using +):

'1st place' -match '[0-9]+'    # $matches[0] is "1" 
'23rd place' -match '[0-9]+'   # $matches[0] is "23"

A range in a character class can be any range of ASCII characters, such as the following examples:

  • a-z
  • A-K
  • 0-9
  • 1-5
  • !-9 (0-9 and the ASCII characters 33 to 47)

The following returns true as " is character 34 and # is character 35 that is, they are within the range !-9:

PS> '"#' -match '[!-9]+'; $matches[0]
True
"#

The range notation allows...