Powershell - add extra column called RoleUserA* inside CSV file-CodePudding

I want to add an extra, empty column called RoleUserA* to a CSV file, as attempted below. RoleUserA* is not an AD Attribute.

Get-ADUser -Filter {Enabled -eq $true} -Properties * | 
  Select givenName, sn, displayname, samaccountname, RoleUserA*, title |
    Export-Csv -Path "c:\tmp\users.csv" -NoTypeInformation -Encoding UTF8

Desired output:

givenName,sn,displayname,samaccountname,RoleUserA*,title
user01,sn1,User01 SN,user01,,specialist
user02,sn2,User02 SN,user02,,specialist

However, RoleUserA* isn't being added as a column.

CodePudding user response：

The (positionally implied) -Property parameter of the Select-Object cmdlet (whose built-in alias is select) interprets its arguments as wildcard expressions.

Therefore, RoleUserA* looks for existing properties on the input objects whose name starts with RoleUserA - and simply adds none to the output objects if no existing property matches; a simple example:

# Because 'bar*' matches no existing properties, it is *ignored*.
PS> [pscustomobject] @{ foo = 1 } | Select-Object foo, bar*

foo
---
  1

While escaping * as `* ('RoleUserA`*') so that it is used literally, as a (non-existent, in this case) property name, should be possible, it unfortunately isn't as of PowerShell 7.2.2,^[1] as Mathias R. Jessen points out, and he also points to the solution that does work:

Use a calculated property, whose Name entry (shortened to n below) is always treated literally; using { $null } as the Expression (e) entry script block creates the property with value $null:^[1]

Get-ADUser -Filter 'Enabled -eq $true' -Properties * | 
  Select givenName, sn, displayname, samaccountname, @{n='RoleUserA*';e={ $null }}, title |
    Export-Csv -Path "c:\tmp\users.csv" -NoTypeInformation -Encoding UTF8

Note: In scripts used long-term, it's better to spell out the entry keys of the calculated property in full, i.e.:

@{ Name = 'RoleUserA*'; Expression = { $null } }

^{[1] This should be considered a bug, or at least needs documenting - see GitHub issue #17068}

^{[2] Using just { } - i.e. an empty script block, almost works the same, but it actually creates an "Automation Null" value (the System.Management.Automation.Internal.AutomationNull.Value singleton), which in expressions behaves the same as $null, but acts differently in a pipeline - see this answer for more information.
That said, in the context of converting to CSV this difference won't matter.}