This chapter makes use of the following on the Windows platform:

• Windows PowerShell 5
• PowerShell Core 6.1

PowerShell is a mixture of a command line, a functional programming language, and an object-oriented programming language. PowerShell is based on Microsoft .NET, which gives it a level of open flexibility that was not available in Microsoft's scripting languages (such as VBScript or batch) before this.

PowerShell is an explorer's scripting language. With built-in help, command discovery, and with access to much of the .NET framework, it is possible to dig down through the layers.

This book is based on PowerShell Core 6.1 with references to PowerShell 5.1; some of the features that are discussed in this book may not be available in the earlier versions of PowerShell.

PowerShell Core may be installed side by side with Windows PowerShell. Preview versions of PowerShell Core can often be installed side by side with full releases of PowerShell Core.

While it is possible to write for PowerShell using the notepad application alone, it is rarely desirable. Using an editor that was designed to work with PowerShell can save a lot of time.

Specialized PowerShell editors such as Visual Studio Code (VS Code), PowerShell Studio, and PowerShell ISE offer automatic completion (IntelliSense), which reduces the amount of cross-referencing required while writing code. Finding a comfortable editor early on is a good way to ease into PowerShell; memorizing commands and parameters is not necessary.

PowerShell ISE is not planned to be released to support PowerShell 6 at this time. VS Code is the most commonly recommended editor for PowerShell. VS Code is a free open source editor that was published by Microsoft VS Code and may be downloaded from http://code.visualstudio.com.

The PowerShell extension should be installed,...

Gaining confidence using the built-in help system is an important part of working with PowerShell. In PowerShell, help is extensive; authors can easily write their own help content when working with functions, scripts, and script modules.

A number of commands are available to interact with the help system, as follows:

• Get-Help
• Save-Help
• Update-Help

Before exploring these commands, the concept of Updatable help should be discussed, as help may not be present on a system after installation.

Updatable help was introduced with PowerShell 3. It gives authors the option to store the most recent versions of their help documentation outside of PowerShell on web servers.

Commands in PowerShell are formed around verb and noun pairs in the form verb-noun.

This feature is useful when finding commands; it allows you to make educated guesses so that there is little need to memorize long lists of commands.

The list of verbs is maintained by Microsoft. This formal approach to naming commands greatly assists in discovery.

Verbs are words such as Add, Get, Set, and New. In addition to these, we have ConvertFrom and ConvertTo.

The list of verbs that are available in PowerShell can be accessed as follows:

Get-Verb 

Each verb has a group, such as data, life cycle, or security. Complementary actions such as encryption and decryption tend to use verbs in the same group...

As we saw while looking at syntax in Get-Help, commands accept a mixture of parameters. The following sections show how these parameters are described in help and how to use them.

When viewing help for a command, we can see many different approaches to different parameters.

Optional parameters are surrounded by square brackets. This denotes an optional parameter that requires a value when used:

SYNTAX
    Get-Process [-ComputerName <String[]>] ...

In this case, if a value for a parameter is to be specified...

Providers in PowerShell present access to data that is not normally easily accessible. There are providers for the filesystem, registry, certificate store, and so on. Each provider arranges data so that it resembles a filesystem.

A longer description of Providers may be seen by viewing the about file:

Get-Help about_Providers

The list of providers available in the current PowerShell session may be viewed by running Get-PSProvider, as shown in the following example:

PS> Get-PSProvider
  
Name           Capabilities                       Drives 
----           ------------                       ------ 
Registry       ShouldProcess, Transactions        {HKLM, HKCU}
Alias          ShouldProcess   ...

Splatting is a technique that was introduced all the way back in PowerShell 2. Splatting is a way of defining the parameters of a command before calling the command. This is an important and often underrated technique.

Individual parameters are written in a hashtable (@{}), and then the @ symbol is used to tell PowerShell that the content of the hashtable should be read as parameters.

This example supplies the Name parameter for the Get-Process command, and is normally written as Get-Process -Name explorer:

$getProcess = @{
    Name = 'explorer'
}
Get-Process @getProcess

In this example, getProcess is used as the name of the variable for the hashtable. The name is arbitrary; any variable name can be used.

Splatting may be used with cmdlets, functions, and scripts. Splatting may be used when the call operator is present, for example:

$getProcess...

In this chapter, we explored the help system that's built into PowerShell. We took a brief look at syntax, examples, and parameters. We also looked at how help content may be moved between computers.

Command naming and discovery introduced how we might use the verb-noun pairing to discover commands that can be used. Aliases were introduced briefly.

Parameters and parameter sets were explored, as well as different types of parameters.

We took a basic look at providers and how they are used before taking a look at handling long command lines using splatting.

In Chapter 2, Modules and Snap-ins, we will explore the commands that are used to find, install, and load modules in PowerShell.