powershell 2.0 redirection file handle exception

Question

I\'m looking for a solution to the The OS handle\'s position is not what FileStream expected. Do not use a handle simultaneously in one FileStream and in Win32 code or

Answer 1

If you do this in foo.ps1 it solves the problem:

# <fix>
$bindingFlags = [Reflection.BindingFlags] "Instance,NonPublic,GetField"
$objectRef = $host.GetType().GetField( "externalHostRef", $bindingFlags ).GetValue( $host )
$bindingFlags = [Reflection.BindingFlags] "Instance,NonPublic,GetProperty"
$consoleHost = $objectRef.GetType().GetProperty( "Value", $bindingFlags ).GetValue(     $objectRef, @() )
[void] $consoleHost.GetType().GetProperty( "IsStandardOutputRedirected", $bindingFlags).GetValue( $consoleHost, @() )
$bindingFlags = [Reflection.BindingFlags] "Instance,NonPublic,GetField"
$field = $consoleHost.GetType().GetField( "standardOutputWriter", $bindingFlags )
$field.SetValue( $consoleHost, [Console]::Out )
$field2 = $consoleHost.GetType().GetField( "standardErrorWriter", $bindingFlags )
$field2.SetValue( $consoleHost, [Console]::Out )
# </fix>

write-host "normal"
write-error "error"
write-host "yay"

powershell .\bar.ps1 2>&1 | more

Piping the output through more hides the fact that it is ultimately going to a file from the child instance of Powershell, bypassing the bug.

In fact, if you create a grandparent script foobar.ps1 which just runs foo.ps1:

powershell .\foo.ps1 2>&1 | more

Then you don't need "the fix" at all, and foo.ps1 can just be

write-host "normal"
write-error "error"
write-host "yay"

.\bar.ps1

because the piping solves the problem for all descendent scripts.