Functions/GenXdev.Windows/Get-ActiveUser.ps1
|
<##############################################################################
Part of PowerShell module : GenXdev.Windows Original cmdlet filename : Get-ActiveUser.ps1 Original author : René Vaessen / GenXdev Version : 1.300.2025 ################################################################################ Copyright (c) René Vaessen / GenXdev Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ################################################################################> ############################################################################### <# .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.' } } } |