How to Check if User Exists in PowerShell

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Sheeraz Gul Feb 02, 2024
PowerShell PowerShell User
How to Check if User Exists in PowerShell

This tutorial demonstrates how to check if a user exists in PowerShell.

PowerShell Check if User Exists

PowerShell provides a command based on the active directory, which is used to check whether a user exists. To use this command, first, we need to import the module ActiveDirectory; the syntax for this command is below.

Get-ADUser

Now follow the steps below to check if a user exists using PowerShell:

  • First, we need to import the module ActiveDirectory. Run the following command:
    Import-Module ActiveDirectory
  • Once the module is imported, we assign the user name to a variable.
  • Then, we create a user variable using the Get-ADUser in a try-catch block.
  • Finally, we check the user variable using the if-else condition to determine if it is null or has some value.
  • Run the following commands for the above three steps:
$UserName = "Sheeraz"
$CheckUser = $(try { Get-ADUser $UserName } catch { $null })
If ($CheckUser -ne $Null) {
    "User exists in the Active Directory"
}
Else {
    "User not found in the Active Directory"
}

The above code will check for the user in the active directory and print the output based on the result. See the output:

User not found in the Active Directory

We can also check multiple users at once. Follow the steps below to check if multiple users exist in the active directory or not:

  • First of all, create an object of users that includes all users’ names.
  • Then run a foreach loop to check each user.
  • Use try-catch blocks to check that each user is similar to the above method.
  • Use the if-else condition to print the results. See the command based on these steps.
$CheckUsers = @("Sheeraz", "Jhon", "Mike")
foreach ($CheckUser in $CheckUsers) {
    $UserObject = $(try { Get-ADUser $CheckUser } catch { $Null })
    If ($UserObject -ne $Null) {
        Write-Host "The user $CheckUser already exists" -ForegroundColor "green"
    }
    else {
        Write-Host "The user $CheckUser does not exists " -ForegroundColor "red"
    }
}

What if we have a large number of users to check? We can use a CSV file with the Get-ADUser command to check many users.

Follow the steps below:

  • First of all, create an empty object of results.
  • Import the CSV with user names.
  • Then run a foreach loop to check each user.
  • Use try-catch blocks to check that each user is similar to the above method.
  • Use the if-else condition to show the results. See the command based on these steps.
$UsersResult = @()
Import-Csv 'C:\Users\Admin\demo.csv' | ForEach-Object {
    $CheckUser = $_."UserName"
    $UserObject = $(try { Get-ADUser $CheckUser } catch { $Null })
    If ($UserObject -ne $Null) {
        $ExistUser = $true
    }
    else {
        $ExistUser = $false
    }
    $UsersResult += New-Object PSObject -Property @{
        UserName  = $CheckUser
        ExistUser = $ExistUser 
    }
}
$UsersResult | select UserName, ExistUser

Our CSV file contains 20 names of different users. The code above will check for each user and print true if the user exists and print false if the user doesn’t exist.

See the output:

UserName ExistUser
-------- ---------
             False
             False
             False
             False
             False
             False
             False
             False
             False
             False
             False
             False
             False
Author: Sheeraz Gul
Sheeraz Gul avatar Sheeraz Gul avatar

Sheeraz is a Doctorate fellow in Computer Science at Northwestern Polytechnical University, Xian, China. He has 7 years of Software Development experience in AI, Web, Database, and Desktop technologies. He writes tutorials in Java, PHP, Python, GoLang, R, etc., to help beginners learn the field of Computer Science.

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