PowerShell 2.0: Quick Tip – Capture Verbose, Error & Warning Streams

update: missing backtick ` to escape the $verbosepreference variable

A question came up on stack overflow (you don’t know what that is? shame on you!) today from someone asking how they could capture the Verbose stream from a pipeline they ran in a C# program. As it turns out, the same technique is used in script, so I’ll give that example instead since I’m sure the C# guys and gals will have no problem converting the script.

The key is using the new (to v2.0) System.Management.Automation.PowerShell Type, which has a built-in Type Accelerator of [powershell]. It has a static method, Create, which is used to create an instance. This instance is pretty much ready to roll. It has a Streams property, which is of Type PSDataStreams. This Type has properties representing each collection of Error, Progress, Verbose, Debug and Warning.

$ps = [powershell]::create()
$ps.Commands.AddScript("`$verbosepreference='continue'; write-verbose 42")
$ps.invoke()
$ps.streams.verbose
Which yields the VerboseRecord that was written out:
Message InvocationInfo                              PipelineIterationInfo
------- --------------                              ---------------------
42      System.Management.Automation.InvocationInfo {0, 0}
What's important to note about the above example is that I had to set the $verbosepreference to at least "continue" (the default is silentlycontinue) in order for the verbose record to be written. Have fun!
blog comments powered by Disqus

About the author

Irish, PowerShell MVP, .NET/ASP.NET/SharePoint Developer, Budding Architect. Developer. Montrealer. Opinionated. Montreal, Quebec.

Month List

Page List