As explained in the previous part, PowerShell uses the $ConfimPreference automatic variable as part of its risk mitigation system: whenever a PowerShell command’s own “ConfirmImpact” is higher or equal to the setting in $ConfirmPreference, PowerShell will show an automatic confirmation dialog.
As a function or script author, you set the “impact level” of your function or script with the attribute CmdletBinding():
function Remove-Something { [CmdletBinding(ConfirmImpact='Medium')] param ( [Parameter(Mandatory)] [string] $Name ) "You entered $Name" }
The sample function Remove-Something has declared its ConfirmImpact to be “Medium”, so when you run it, PowerShell will trigger auto-confirmation when $ConfirmPreference is set to at least “Medium”.
Binary cmdlets do the very same. To find out the confirm impact of binary cmdlets, you can use the function below:
filter Get-ConfirmInfo { param ( [Parameter(Mandatory,ValueFromPipeline)] [string] $CommandName ) $CommandInfo = Get-Command -Name $CommandName [System.Management.Automation.CommandMetaData]::new($CommandInfo) | Select-Object -Property Name, ConfirmImpact, SupportsShouldProcess }
When you submit command names to it, it will reveal the ConfirmImpact defined by the command author, plus whether the command supports simulation switches such as -WhatIf (in which case SupportsShouldProcess shows $true).
PS> 'Get-Random', 'Remove-Item', 'Stop-Process' | Get-ConfirmInfo Name ConfirmImpact SupportsShouldProcess ---- ------------- --------------------- Get-Random Medium False Remove-Item Medium True Stop-Process Medium True
Since Get-ConfirmInfo is pipeline-aware, you can even investigate your PowerShell command set and search for High impact cmdlets:
PS> Get-Command -Verb Remove | Get-ConfirmInfo | Where-Object ConfirmImpact -eq High Name ConfirmImpact SupportsShouldProcess ---- ------------- --------------------- Remove-CIAccessControlRule High True Remove-CIVApp High True Remove-CIVAppNetwork High True Remove-CIVAppTemplate High True Remove-BCDataCacheExtension High True Remove-ClusterAffinityRule High True Remove-ClusterFaultDomain High True (...)
