How to Tell if Cmdlet Parameters are Mandatory or Optional?

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Steps to reproduce

This is not a bug report, but rather a question on how to interpret the PowerShell documentation (man pages).

My question is: How does one tell which cmdlet parameters are required, and which are optional?

I know how mandatory parameters are declared in code ([Parameter(mandatory = true)]), but not how to determine that from the documentation Web pages.

For example, the Write-Progress page (https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/write-progress?view=powershell-7.3) shows A number of parameters, but the -Activity parameter is not enclosed in square brackets like the others. Does that mean the -Activity parameter is mandatory and the others optional? Or am I reading too much into the format?

Is there a way to determine which parameters for a cmdlet are required, other than trial and error experimentation?

Expected behavior

N/A

Actual behavior

N/A

Error details

No response

Environment data

PSVersion                      7.3.4
PSEdition                      Core
GitCommitId                    7.3.4
OS                             Microsoft Windows 10.0.19045
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Visuals

No response

[237dmitry]

You can find mandatory parameters with Get-Command, for example in Export-Csv:

(Get-Command Export-Csv).Parameters.Values.where{ $_.ParameterSets.Values.IsMandatory }.Name

[jhoneill]

A cut and paste from @237dmitry 's example works for me. Get-Command itself doesn’t have any manadatory parameters.

(Get-Command write-progress).Parameters.Values.where{ $_.ParameterSets.Values.IsMandatory }.Name

returns “Activity” for me .

This builds on his example.

(Get-Command Where-Object).Parameters.Values  | format-Table -auto -wrap -property Name ,@{n="Used in Set(s)";e = {$(foreach ($k in $_.parameterSets.keys) {if ($_.parameterSets[$k].IsMandatory) {"$k Manadatory"} else {"$k optional"}  }) -join "; " } }

A cut and paste will show just how complicated where-object is. If you change where object to get-command or write-progress you’ll get something simpler.