Here is a collection of tips and tricks to debug PowerShell<\/p>\n
Read Up Clean code Note, there\u2019s a lot of normal PowerShell (v1 and V2) that StrictMode barfs on, so its recommend to only use Set-StrictMode when trying to debug their own scripts.<\/p>\n You can also change your error, and warning preference to make PowerShell stop at non-terminating errors or warning. This makes sure that if any errors are raised, whether they are terminating or non-terminating, code will stop. Calling .net methods that throw exceptions are an example of a non-terminating error. In C#, they would be terminating.<\/p>\n Error information $LASTEXITCODE tells you if a native command completed successfully or not. For example \u201cping example.com\u201d gives $LASTEXITCODE of 1<\/p>\n $? Tells you if the last command had any error in it. This includes if you tried to execute a command that does not exist. Pping will not set $LASTEXITCODE, but it will set $? To False<\/p>\n Trapping and Catching errors Tracing Write-Output is usually a better alternative… Write-Host can\u2019t be captured into log files.<\/p>\n More info on Write-Host and Write-Output is here http:\/\/blogs.msdn.com\/monad\/archive\/2005\/11\/09\/490625.aspx<\/a><\/p>\n Use the ISE Debugger
<\/strong>There is a 7-part series of \u201cDebugging Monad Scripts<\/a>\u201d that Jon Newman wrote a few years ago that covers a lot of tips, including error handling, traps, tracing, and covers a lot of V1 stuff.<\/p>\n
<\/strong>The best route, is to make sure code is clean, and common errors are caught. To do so, run
Set-StrictMode -Version 2<\/p>\n
For example, $ErrorActionPreference = ‘stop’ or $WarningPreference = ‘stop’<\/p>\n\n
<\/strong>$error holds the error information from commands. To get more details information, try
$error | select -ExpandProperty Exception | Format-List -f *
$error is explained here https:\/\/blogs.msdn.com\/powershell\/archive\/2006\/04\/25\/583229.aspx<\/a>
A better Resolve-Error function from Jeffery can be found here http:\/\/blogs.msdn.com\/powershell\/archive\/2006\/12\/07\/resolve-error.aspx<\/a><\/p>\n
<\/strong>Try\/catch and trap can be used to process errors<\/p>\n\n
<\/strong>Write-Debug will write messages to the screen. You need to set, $DebugPreference = “continue”, so they actually appear. Setting $DebugPreference and $VerbosePreference can sometimes give you clues on what other commands are doing.
Write-Host is a more normal\/boring way of getting output. Out-Host is sometimes better because it preserves format and output<\/p>\n
<\/strong>The ISE comes with a debugger that helps you to see the callstack, set and hit breakpoints, step over, into and out of your code. Find more information here – http:\/\/blogs.msdn.com\/powershell\/archive\/2009\/01\/19\/debugging-powershell-script-using-the-ise-editor.aspx<\/a><\/p>\n