Functions/GenXdev.Windows/Get-ActiveUser.ps1
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Part of PowerShell module : GenXdev.Windows Original cmdlet filename : Get-ActiveUser.ps1 Original author : René Vaessen / GenXdev Version : 1.270.2025 ################################################################################ MIT License Copyright 2021-2025 GenXdev Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ################################################################################> ############################################################################### <# .SYNOPSIS Retrieves a list of unique usernames from currently active system processes. .DESCRIPTION Queries all running processes on the system, extracts the associated username for each process, and returns a deduplicated list of users who have active processes. This is useful for system administration and security monitoring. .EXAMPLE Get-ActiveUser Returns a list of all unique usernames with active processes. .EXAMPLE gusers Uses the alias to get the same results. ###############################################################################> function Get-ActiveUser { [CmdletBinding()] [Alias('gusers')] param() begin { # store original error preferences for restoration $originalEAP = $ErrorActionPreference $originalErrorView = $ErrorView # set strict error handling $ErrorActionPreference = 'Stop' $ErrorView = 'DetailedView' # inform about the start of process enumeration Microsoft.PowerShell.Utility\Write-Verbose 'Starting to enumerate all system processes...' } process { try { # get all processes with associated usernames (requires admin privileges) $processes = Microsoft.PowerShell.Management\Get-Process * ` -IncludeUserName ` -ErrorAction Stop # extract and deduplicate usernames from process list $users = $processes | Microsoft.PowerShell.Core\ForEach-Object UserName | Microsoft.PowerShell.Utility\Select-Object -Unique # return the filtered list $users } catch [System.UnauthorizedAccessException] { Microsoft.PowerShell.Utility\Write-Error ` -Message 'Access denied while retrieving processes. Run with elevated privileges.' ` -Exception $_.Exception ` -Category PermissionDenied ` -ErrorId 'ActiveUserAccessDenied' throw } catch [System.ArgumentException] { Microsoft.PowerShell.Utility\Write-Error ` -Message 'Invalid argument provided when retrieving processes.' ` -Exception $_.Exception ` -Category InvalidArgument ` -ErrorId 'ActiveUserInvalidArgument' throw } catch { Microsoft.PowerShell.Utility\Write-Error ` -Message "Unexpected error while retrieving active users: $_" ` -Exception $_.Exception ` -Category OperationStopped ` -ErrorId 'ActiveUserUnexpectedError' throw } } end { # restore original error handling settings $ErrorActionPreference = $originalEAP $ErrorView = $originalErrorView # output completion status if users were found if ($null -ne $users) { Microsoft.PowerShell.Utility\Write-Verbose ` "Process completed. Found $($users.Count) unique active users." } else { Microsoft.PowerShell.Utility\Write-Verbose ` 'Process completed. No active users found or an error occurred.' } } } |