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
- A Sample of PowerShell’s Help About Topics
- The Point of Get-Help about_Topic
- Example of PowerShell About_
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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"
Solution: $ConfirmPreference = "None"
Result: PowerShell surpresses the above 'Confirm' dialog box.
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.
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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.
