10 PowerShell Mistakes, Trips and Traps

10 PowerShell Mistakes, Trips and Traps

• 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 USEWRITE-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 ALLABOUT 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 AREOBJECTS, TOO • $True and $False are not strings • The cool PowerShell kids don’t compare
• 6.
  #4 DON’T FALLINTO 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 ISNOT .NET PROGRAMMING • Use cmdlets wherever possible • .NET classes and methods are for exceptions • …or large scale performance benefits
• 9.
  #7 POWERSHELL ISNOT VBSCRIPT • PowerShell requires a new paradigm • Don’t turn VBScript into PowerShell • Objects in the pipeline
• 10.
  #8 DON’T MAKEERRORS 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-INVENTTHE 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 EVERYTHINGIS 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 • Writeobjects 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 • LearnPowerShell 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 [email protected] @JeffHicks http://gplus.to/jeffhicks