Understanding Important Windows PowerShell Concepts

The Windows PowerShell design integrates concepts from many different environments. Several of them are familiar to people with experience in specific shells or programming environments, but very few people will know about all of them. Looking at some of these concepts provides a useful overview of the shell.

Commands are not Text-based

Unlike traditional command-line interface commands, Windows PowerShell cmdlets are designed to deal with objects - structured information that is more than just a string of characters appearing on the screen. Command output always carries along extra information that you can use if you need it. We will discuss this topic in depth in this document.

If you have used text-processing tools to process command-line data in the past, you will find that they behave differently if you try to use them in Windows PowerShell. In most cases, you do not need text-processing tools to extract specific information. You can access portions of the data directly by using standard Windows PowerShell object manipulation commands.

The Command Family is Extensible

Interfaces such as Cmd.exe do not provide a way for you to directly extend the built-in command set. You can create external command-line tools that run in Cmd.exe, but these external tools do not have services, such as help integration, and Cmd.exe does not automatically know that they are valid commands.

The native binary commands in Windows PowerShell, known as cmdlets (pronounced command-lets), can be augmented by cmdlets that you create and that you add to Windows PowerShell by using snap-ins. Windows PowerShell snap-ins are compiled, just like binary tools in any other interface. You can use them to add Windows PowerShell providers to the shell, as well as new cmdlets.

Because of the special nature of the Windows PowerShell internal commands, we will refer to them as cmdlets.

Installing and Running Windows PowerShell

Installation Requirements

Before you install Windows PowerShell, be sure that your system has the software programs that Windows PowerShell requires. Windows PowerShell requires the following programs:

· Windows XP Service Pack 2, Windows 2003 Service Pack 1, or later versions of Windows

· Microsoft .NET Framework 2.0

If any version of Windows PowerShell is already installed on the computer, use Add or Remove Programs in Control Panel to uninstall it before installing a new version.

Installing Windows PowerShell

To install Windows PowerShell:

1. Download the Windows PowerShell installation file. (The name of the file will differ with the platform, operating system, and language pack.)

2. To start the installation, click Open.

3. Follow the instructions on the installation wizard pages.

You can also save the Windows PowerShell files to a network share for installation on multiple computers.

To perform a silent installation, type:

<PowerShell-exe-file-name> /quiet

For example,

PowerShellSetup_x86_fre.exe /quiet

On 32-bit versions of Windows, Windows PowerShell is installed, by default, in the %SystemRoot%\System32\WindowsPowerShell\v1.0  directory. On 64-bit versions of Windows, a 32-bit version of Windows PowerShell is installed in the %SystemRoot%\SystemWow64\WindowsPowerShell\v1.0 directory and a 64-bit version of Windows PowerShell is installed in the %SystemRoot%\System32\WindowsPowerShell\v1.0 directory.

Running Windows PowerShell

To start Windows PowerShell from the Start Menu, click Start, click All Programs, click Windows PowerShell 1.0, and then click the Windows PowerShell icon.

To start Windows PowerShell from the Run box, click Start, click Run, type powershell, and click OK.

To start Windows PowerShell from a Command Prompt (cmd.exe) window, at the command prompt, type powershell. Because Windows PowerShell runs in a console session, you can use this same technique to run it within a remote telnet or SSH session. To return to your Command Prompt session, type exit.