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PowerShell Help About_ Files

Windows PowerShell Help Files

PowerShell has a selection of about_ files. It's a pity that stay these trees-of-wisdom stay in the shadows of the help for Verb-Noun cmdlets.  The purpose of this page is to alert you to the interesting information in these lesser known about_Topic files.

Topics for PowerShell Help About_ Files

 ♣

Listing All PowerShell's About Files

# PowerShell's About_files
Get-Help About* | Format-Wide Name -AutoSize

Note 1: Here above is a rare use for Format-Wide.

A Sample of PowerShell's About Topics

about_Arithmetic_Operators
about_Arrays
about_Command_Precedence
about_Environment_Variables
about_For
about_Foreach
about_Functions
about_Hash_Tables
about_If
about_Logical_Operators
about_Quoting_Rules
about_Preference_Variables
about_Switch 
about_Regular_Expressions
about_Remote

Note 2: You can get a total with: (Get-Help about).count.  I make it nearly 100 'about_' files in PowerShell 3.0.

The Point of Get-Help about_Topic

Each of PowerShell's regular cmdlets, whatever their Command Type, has it's own help file.  The problem is where does than leave help for conditional operators such as -Match, or logic structures such as ElseIf?

The answer is the information is in the respective about_file.  Each topic is full of useful advice on its syntax, and provides examples to get you started.

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Example of PowerShell About_

Let us see how we can get help about PowerShell's quotation marks, here is an extract from the help file:

Get-Help About_Quoting_Rules

DESCRIPTION
Quotation marks are used to specify a literal string. You can enclose a string in single quotation marks (') or double quotation marks (").

Single and Double-Quoted Strings

When you enclose a string in double quotation marks (a double-quoted string), variable names that are preceded by a dollar sign ($) are replaced with the variable's value before the string is passed to the command for processing.

For example:

$i = 5
"The value of $i is $i."

The output of this command is:
The value of 5 is 5.

However:
When you enclose a string in single-quotation marks (a single-quoted string), the string is passed to the command exactly as you type it. No substitution is performed. For example:

$i = 5
'The value of $i is $i.'

The output of this command is:
The value $i is $i.

Get-Help about_Preference_Variables

Problem: You get interactive prompts, for example with Remove-Item.

Clear-Host
$ConfirmPreference = "Low"
$Source = "D:\Pshell"
Copy-Item -Path $Source -Destination $ClearOut -Recurse
$ClearOut = "D:\Bad Stuffs\"
Remove-Item $ClearOut -Recurse

Note 3: To get my script working change the values of the variables $Source and $ClearOut.

Note 4: This is the result of Remove-Item with $ConfirmPreference = "Low"

about_Preference_Variables

Solution: $ConfirmPreference = "None"

Result: PowerShell surpresses the above 'Confirm' dialog box.

See more about -Confirm ยป

Summary of PowerShell's Help About_files

Windows PowerShell has a library of 'about_ files'.  You can list their names with Help about*, then use Get-Help once more to read the individual topics.

If you like this page then please share it with your friends

 


See more Windows PowerShell tutorials

PShell Home   • Introduction   • Dreams   • 3 Key Commands   • PowerShell Help About   • Get-Help

PowerShell v 3.0   • Set-ExecutionPolicy   • Get-Command   • Cmdlet scripts   • Import-Module

PowerShell Version Check   • Backtick   • PowerShell examples   • PowerShell ISE   • Get-Member

Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.

 

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