Solved

powershell - check for exisiting AD User

Posted on 2016-10-19
4
57 Views
Last Modified: 2016-10-19
Very simple powershell function (part below) . No matter what the $username variable is I always get the message 'User already exists'. Obviously I am trying with nonsense usernames that definitely don't exist as well as those that do. what's going on?

-----

Function CreateStaff ()
{
# Check if an AD User of that name already exists
$ADUserCheck = get-aduser -Identity $username -ErrorAction SilentlyContinue

    If ($ADUserCheck -eq $null)
      {
        Write-Host "User does not already exist, creating staff user..."
      }
     
    Else
      {
      Write-Warning "$username already exists"
      }
}
0
Comment
Question by:Pete
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 84

Expert Comment

by:oBdA
ID: 41850215
When a cmdlet errors out, it returns nothing, not $Null, so ($ADUserCheck -eq $null) will always be $False.
Just drop the "-eq $Null" and reverse the logic:
Function CreateStaff () {
	# Check if an AD User of that name already exists
	$ADUserCheck = Get-ADUser -Identity $username -ErrorAction SilentlyContinue
    If ($ADUserCheck) {
		Write-Warning "$username already exists"
	} Else {
		Write-Host "User does not already exist, creating staff user..."
	}
}

Open in new window

0
 
LVL 1

Author Comment

by:Pete
ID: 41850235
OK, now when I enter a unique username (so it should create a user) I get the error:

---

get-aduser : Cannot find an object with identity: 'thisisausername' under: 'DC=domain,DC=LOCAL'.
At .ps1:190 char:16
+ ... UserCheck = get-aduser -Identity $username -ErrorAction SilentlyConti ...
+                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (SDFSDFSDFSDFS:ADUser) [Get-ADUser], ADIdentityNotFoundException
    + FullyQualifiedErrorId : ActiveDirectoryCmdlet:Microsoft.ActiveDirectory.Management.ADIdentityNotFoundExcep
   tion,Microsoft.ActiveDirectory.Management.Commands.GetADUser
0
 
LVL 40

Assisted Solution

by:Subsun
Subsun earned 150 total points
ID: 41850244
Using -ErrorAction SilentlyContinue may not suppress the error, use Try catch method, and you also need to define a parameter.
Function CreateStaff ($Username) {
	$ADUserCheck = Try {Get-ADUser -Identity $username}Catch{}
    If ($ADUserCheck) {
		Write-Warning "$username already exists"
	} Else {
		Write-Host "User does not already exist, creating staff user..."
	}
}

CreateStaff UserA

Open in new window

Or use Filter or LDAPFilter
$ADUserCheck = Get-ADUser -LDAPFilter "(sAMAccountName=$Username)"

Open in new window

0
 
LVL 84

Accepted Solution

by:
oBdA earned 350 total points
ID: 41850265
Catch (only) the ADIdentityNotFoundException, in case something else in AD isn't working:
Function CreateStaff () {
	# Check if an AD User of that name already exists
	Try {
		$ADUserCheck = Get-ADUser -Identity Bla -ErrorAction SilentlyContinue
	} Catch [Microsoft.ActiveDirectory.Management.ADIdentityNotFoundException] {
	}
    If ($ADUserCheck) {
		Write-Warning "$username already exists"
	} Else {
		Write-Host "User does not already exist, creating staff user..."
	}
}

Open in new window

0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

"Migrate" an SMTP relay receive connector to a new server using info from an old server.
The following article is intended as a guide to using PowerShell as a more versatile and reliable form of application detection in SCCM.
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…

696 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question