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WHY POWERSHELL? 5
What Is PowerShell, and Why Do You Need It?
CHAPTER 1
as the registry, certi cate store, and Windows Management Instrumentation (WMI).
WMI is a core technology for Windows system administration, because it exposes a
wide range of information in a uniform manner. PowerShell includes a cmdlet that
allows you to interface with WMI objects, enhancing your ability to do real work.
But isn’t PowerShell just a command-line tool? Yes, it is a command-line tool, but in
most cases PowerShell can accomplish all the tasks that graphic management tools can.
PowerShell is built upon a robust architecture that includes the following:
▶ A script parser that processes language constructs, such as scripts, predicates,
and conditionals
▶ A pipeline processor, which manages intercommand communication using
pipes ( | )
▶ A command processor, which manages command execution, registration, and
associated metadata
In addition to those processors, the shell can also manage session state and has an
extended type system, which exposes a common interface for accessing properties
and methods independent of the underlying object type. Lastly, PowerShell includes
a robust error handler for managing error exceptions and error reporting.
The Power Behind PowerShell
PowerShell is built around an object-oriented language that lets you manage your
Windows infrastructure. It provides an interface and programming environment that
allows users and administrators to access and set system properties through .NET
objects and single-function command-line tools called cmdlets. Cmdlets are the building
blocks for PowerShell scripts. Chapter 3 explores cmdlets and the core PowerShell syntax.
 e scripting language manipulates objects (not text) using the .NET Framework and
the .NET common language runtime. PowerShell is built on top of, and is integrated
with, the Microso .NET Framework. It accepts and returns .NET objects, allowing
for robust scripting that interfaces seamlessly with many line-of-business tools.
 is is the main reason PowerShell is more than just a console application. It is a
robust scripting environment that supports a full range of logical program control,
including simple conditional statements and complex switch statements using
regular expressions to parse conditions. Scripts can be used independently or in
conjunction with other scripts, with .NET Framework or COM objects, or even in
code. PowerShell enables easy access to COM and WMI to provide an environment
for local and remote Windows systems.
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