Basics with Windows Powershell

INTRODUCTION

Microsoft's new command shell/scripting language. This series provides a task-based introduction to Windows PowerShell cmdlets: rather than focusing on the individual cmdlets themselves, the emphasis is on the tasks you can carry out using those cmdlets. These tasks include everything from reading and writing text files to managing event logs to sorting and filtering data. 

Applies To: Windows PowerShell 2.0, Windows PowerShell 3.0, Windows PowerShell 4.0 

Graphical user interfaces use some basic concepts that are well known to most computer users. Users rely on the familiarity of those interfaces to accomplish tasks. Operating systems present users with a graphical representation of items that can be browsed, usually with drop-down menus for accessing specific functionality and context menus for accessing context-specific functionality. 

A command-line interface (CLI), such as Windows PowerShell, must use a different approach to expose information, because it does not have menus or graphical systems to help the user. You need to know command names before you can use them. Although you can type complex commands that are equivalent to the features in a GUI environment, you must become familiar with commonly-used commands and command parameters. 

Most CLIs do not have patterns that can help the user to learn the interface. Because CLIs were the first operating system shells, many command names and parameter names were selected arbitrarily. Terse command names were generally chosen over clear ones. Although help systems and command design standards are integrated into most CLIs, they have been generally designed for compatibility with the earliest commands, so the command set is still shaped by decisions made decades ago. 

Windows PowerShell was designed to take advantage of a user's historic knowledge of CLIs. In this chapter, we will talk about some basic tools and concepts that you can use to learn Windows PowerShell quickly. They include: 

•  Using Get-Command 

•  Using Cmd.exe and UNIX commands 

•  Using External Commands 

•  Using Tab-Completion 

•  Using Get-Help 

for example, they mention that using double quotes you can evaluate variables inside the strings: 

$x = hello

$x world

results in hello world 

but 

$y = hello,goodbye

$y[0] world 

does not. So, trial and error commence and we try: 

${y[0]} world which also fail. 

It would be a lot better if they bothered to explain exactly how the various basic tokens are built up, for example what goes into a script block? will for example: 

$x=hello

0..4 | foreach-object -process { $x world $_ } 

Give the expected result? Yes, it does! 

But for some reason using $args inside foreach does not - because presumably foreach-process has it's own arguments which replaces the $args variable, probably best then to store the $args into another variable and then use it? Yes, that works. 

Things would be a lot easier if they bothered to have a few chapters to explain these basic stuff rather than having each of us finding out by experimentation. 

Seems they skip immediately to the fun part and drop the tedious basic building blocks of the scripting language. 

Also, if they could allow a character to escape the meaning of $ inside double quoted strings so you could write stuff like:

\$x = '$x'

To get the output 

$x = 'Hello'

but that is not just documentation, that is change of the language. Yes, I know you can get the same

string by doing: 

($+x = '$x')

but it is easier to write \$x = '$x' to achieve the same thing. 

About Windows PowerShell 

Discoverability

Windows PowerShell makes it easy to discover its features. For example, to find a list of cmdlets that view and change Windows services, type: 

get-command *-service 

After discovering which cmdlet accomplishes a task, you can learn more about the cmdlet by using the Get-Help cmdlet. For example, to display help about the Get-Service cmdlet, type: 

get-help get-service 

To fully understand the output of that cmdlet, pipe its output to the Get-Member cmdlet. For example, the following command displays information about the members of the object output by the Get-Service cmdlet. 

get-service | get-member 

Consistency

Managing systems can be a complex endeavor and tools that have a consistent interface help to control the inherent complexity. Unfortunately, neither command-line tools nor scriptable COM objects have been known for their consistency. 

The consistency of Windows PowerShell is one of its primary assets. For example, if you learn how to use the