The document outlines 10 common mistakes made when using PowerShell, including using Write-Host when objects in the pipeline are needed, not treating everything as objects, misusing aliases, ignoring errors, and trying to recreate built-in PowerShell functionality instead of using cmdlets. The author is an MVP with experience in PowerShell training and consulting who provides recommendations on best practices and resources for learning PowerShell.

1. 10 POWERSHELL MISTAKES,
TRIP-UPS AND TRAPS
JEFFERY HICKS
PROF. POWERSHELL

2. WHO AM I?
• Windows PowerShell MVP
• PowerShell Author
• Learn PowerShell 3 in a Month of Lunches (with Don Jones)
• Learn PowerShell Toolmaking in a Month of Lunches (with Don Jones)
• PowerShell in Depth (with Don Jones & Richard Siddaway)
• Managing Active Directory with Windows PowerShell: TFM 2nd Ed.
• IT trainer and consultant
• http://jdhitsolutions.com/blog
• http://twitter.com/jeffhicks

3. #1 DON’T USE WRITE-HOST
• Write-Host writes to the console, not the pipeline
• You can only work with objects written to the pipeline
• Puppies are hurt when you use Write-Host
• Unless you use as intended

4. #2 IT’S ALL ABOUT THE OBJECTS
• Don’t try to parse text
• Don’t try to concatenate
• Everything in PowerShell is an object
• Learn how to use Get-Member

5. #3 BOOLEANS ARE OBJECTS, TOO
• $True and $False are not strings
• The cool PowerShell kids don’t compare

6. #4 DON’T FALL INTO THE ALIAS TRAP
• Aliases are fine for interactive sessions
• You know what you’re typing
• Aliases disguise the real command

7. #5 VARIABLE VULNERABILITY
• This isn’t VBScript
• Variable names should be meaningful
• Avoid re-using variables for different object types

8. #6 POWERSHELL IS NOT .NET PROGRAMMING
• Use cmdlets wherever possible
• .NET classes and methods are for exceptions
• …or large scale performance benefits

9. #7 POWERSHELL IS NOT VBSCRIPT
• PowerShell requires a new paradigm
• Don’t turn VBScript into PowerShell
• Objects in the pipeline

10. #8 DON’T MAKE ERRORS GO AWAY
• Don’t turn off error pipeline
• $ErrorActionPreference = "SilentlyContinue"
• Makes troubleshooting more difficult
• Use Try/Catch and learn how to handle errors

11. #9 DON’T RE-INVENT THE WHEEL
• Don’t try to duplicate PowerShell functionality
• No need to write your own help routine
• Don’t try to re-invent cmdlets using .NET

12. #10 NOT EVERYTHING IS A ONE-LINER
• One-line commands can be efficient
• Great for interactive console
• Not necessarily a benefit in scripting
• Don’t code yourself into a corner

13. QUESTIONS AND ANSWERS

14. RECOMMENDATIONS
• Write objects to the pipeline
• Use cmdlets where possible
• No aliases or shortcuts in scripts
• Learn how to handle errors
• Read the help and examples

15. RESOURCES
• Learn PowerShell 3 in a Month of Lunches by Don Jones and Jeffery
Hicks
• Learn PowerShell Toolmaking in a Month of Lunches by Don Jones
and Jeffery Hicks
• The Lonely Administrator (http://jdhitsolutions.com/blog)
• Prof. PowerShell (http://mcpmag.com/articles/list/prof-powershell.
aspx
• PowerShell.org

16. THANK YOU
http://jdhitsolutions.com/blog
jhicks@jdhitsolutions.com
@JeffHicks
http://gplus.to/jeffhicks