Question

Scripts (with CmdletBinding) and cmdlets all have a standard -ErrorAction parameter available when being invoked. Is there a way then, within your script, if indeed you script was invoked with -ErrorAction?

Reason I ask is because I want to know if the automatic variable value for $ErrorActionPreference, as far as your script is concerned, was set by -ErrorAction or if it is coming from your session level.

Answer 1

$ErrorActionPreference is a variable in the global(session) scope. If you run a script and don’t specify the -ErrorAction parameter, it inherits the value from the global scope ($global:ErrorActionPreference).

If you specify -ErrorAction parameter, the $ErrorActionPreference is changed for your private scope, meaning it’s stays the same through the script except while running code where you specified something else(ex. you call another script with another -ErrorAction value). Example to test:

Test.ps1

[CmdletBinding()]
param()

Write-Host "Session: $($global:ErrorActionPreference)"
Write-Host "Script: $($ErrorActionPreference)"

Output:

PS-ADMIN > $ErrorActionPreference
Continue

PS-ADMIN > .\Test.ps1
Session: Continue
Script: Continue

PS-ADMIN > .\Test.ps1 -ErrorAction Ignore
Session: Continue
Script: Ignore

PS-ADMIN > $ErrorActionPreference
Continue

If you wanna test if the script was called with the -ErrorAction paramter, you could use ex.

if ($global:ErrorActionPreference -ne $ErrorActionPreference) { Write-Host "changed" }

If you don’t know what scopes is, type this in a powershell console: Get-Help about_scopes