Powershell Parameter Parsing – How to Use a Single Parameter to Control Script Process Targeting

    <#
    .PARAMETER ConfigTarget
        Set the ComputerType parameter to determine what computer(s) the script targets.
        Options:
            Enter "Domain" to have the script target all computers pf a specific type in the domain.
            Enter an OU (DN or CN) from which the script will get a computer list.
            Enter a computer name (hostname only).
            Enter a file path the contains a text or csv file containing a computer list.
        PARAMETER ALIAS: Computer or Type or CT
        Example: Update-LocalAdminPw.ps1 -ConfigTarget "Domain"
        Example: Update-LocalAdminPw.ps1 -ConfigTarget "OU=Workstations,OU=ComputerTarget,DC=example,DC=com"
        Example: Update-LocalAdminPw.ps1 -ConfigTarget "example.com\ComputerTarget\Workstations"
        Example: Update-LocalAdminPw.ps1 -ConfigTarget "COMPUTERNAME"
        Example: Update-LocalAdminPw.ps1 -ConfigTarget "c:\temp\computerlist.txt"
    #>

    Param
        (
        [parameter(Mandatory=$False)]
        [alias("Target","OUName","ComputerName","Computer")]
        [string]$ConfigTarget = "Domain",
        )  

    Import-Module ActiveDirectory

    ###############################
    # Format Computer Target List #
    ###############################
    # If $ConfigTarget is a single computername set here

    IF (($ConfigTarget -notlike "*DC=*") -OR ($ConfigTarget -notlike "*/*") -OR ($ConfigTarget -ne "Domain") -OR ($ConfigTarget -notlike "*:\*") -OR ($ConfigTarget -notlike "*,*") )
        {  ## OPEN IF ConfigTarget is a computer name
         [array] $TargetComputerList += $ConfigTarget
        }  ## OPEN IF ConfigTarget is a computer name

    # If $ConfigTarget is a comma delimited list set here    
    IF ($ConfigTarget -like "*,*")
        {  ## OPEN IF comma delimited list
            Write-Output "User list file identified as comma delimited `r "
            $ComputerList = $ConfigTarget -Replace(" ","")
            [array]$ComputerListArray = $ComputerList -split(",")
            [array] $TargetComputerList = $ComputerListArray
        }  ## CLOSE IF comma delimited list

    ########################################
    # Get Computer Target List from a file #
    ########################################

    IF ($ConfigTarget -like "*:\*")
        {  ## OPEN IF File
          $FileCheck = Test-Path $File
          IF ($FileCheck -eq $True)
            { ## OPEN IF The path to the Computers list file is true
              $ComputerList = Get-Content $File
              $ComputerListCount = $ComputerList.Count
              Write-Output "Importing $ComputerListCount Users from $File... `r "
            } ## CLOSE IF The path to the Computers list file is true
          ELSE { Write-Warning "Path to Computer list: $File is invalid. `r " ; exit }          

            IF ($ComputerList -like ",")
                { ## OPEN IF the imported list of Computers is comma delimited
                  Write-Output "User list file identified as comma delimited `r "
                  $ComputerList = $ComputerList -Replace(" ","")
                  [array]$ComputerListArray = $ComputerList -split(",")
                  $Computers = $ComputerListArray
                } ## CLOSE IF the imported list of Computers is comma delimited

        }  ## CLOSE IF File

    ###################################
    # Get a list of computers from OU #
    ###################################

    IF (($ConfigTarget -like "*DC=*") -OR ($ConfigTarget -like "*/*"))
        {  ## OPEN IF OUName is specified
            IF (!$ComputerType) { Write-Warning "When defining the target as an OU, the ComputerType parameter must be defined. `r " ; exit }
            Write-Verbose "Check the OU path info `r "
            IF ($ConfigTarget -like "*DC=*")
                # This identifies the OU input as a DN OU path
                # The OU DN is required for the next component that gathers the computers in the OU path.

                {  ## OPEN IF OUPath contains "DC=" which means it is a DN Name
                    $OUCheck = $True
                    Write-Output "The specified OU path ($ConfigTarget) is already a DN. Continuing...  `r "
                }  ## CLOSE IF OUPath contains "/" which means it is a Canonical Name  

                IF ($ConfigTarget -like "*/*")
                    # This identifies the OU input as a CN OU path which is then converted to be a DN
                    # The OU DN is required for the next component that gathers the computers in the OU path.

                    {  ## OPEN IF OUPath contains "/" which means it is a Canonical Name
                        # Create the array by spitting the text input on the "/"
                        $OUCheck = $True
                        $OUPathArray = $ConfigTarget.split("/")
                        IF ($OUPathArray[0] -like "*.*")
                            {  ## OPEN IF The first item in the array is a domain name
                                $Len = $OUPathArray.length
                                $Len--
                                $Num = 1
                                $NewArray = @(1..$Len)

                                for($i=0; $i -lt $Len; $i++)
                                    {  ## OPEN FOR
                                        $NewArray[$i] = $OUPathArray[$Num]
                                        $Num++
                                    }  ## CLOSE FOR

                                $OUPathArray = $NewArray      
                            }  ## CLOSE IF The first item in the array is a domain name

                        # Reverse the order of the aray to build the DN appropriately
                        [array]::Reverse($OUPathArray)
                        $OUPathCount = $OUPathArray.count

                        # Loop through the OU data to build the DN
                        $OUPath =  "OU="
                        $OUDelimiter = ",OU="
                            For ($CountOU = 0;$CountOU -le $OUPathCount;$CountOU++)
                               {  ## OPEN Bracket FOR loop to ensure the LDAP path is properly built
                                IF ($CountOU -eq 0) {$OUPath = $OUPath + $OUPathArray[0];$CountOU++ }
                                IF ($OUPathArray[$CountOU]) {$OUPath = $OUPath + $OUDelimiter + $OUPathArray[$CountOU]}
                               }  ## CLOSE Bracket FOR loop to ensure the LDAP path is properly built

                        # Build the full DN by appending the domain DN to the OUPath created in the loop above
                        $ComputerTargetOU = "$OUPath,$ADDomainDistinguishedName"
                        write-output " `r "
                        write-output "OU is now set to $ComputerTargetOU `r "
                        write-output " `r "
                    }  ## CLOSE IF OUPath contains "/" which means it is a Canonical Name                            

                   IF ($OUCheck -eq $False)
                       { Write-Warning "OU entered ($ConfigTarget) is not a valid Canonical Name or Distinguished Name.  Exiting... `r " ; exit }  

                       Switch ($ComputerType)
                        # This determines what type of computer object is returned: workstation or server
                        {  ## OPEN Switch ComputerType

                          Workstation
                           {  ## OPEN Switch Workstation Option
                            # Gather a list of all active workstations in specified OU tree including necessary attributes
                            write-output "Discovering active workstations in $ComputerTargetOU ..." `r
                             $AllActiveWorkstations = Get-ADComputer  -SearchBase $ComputerTargetOU -filter {(OperatingSystem -like "*Windows*") -and (OperatingSystem -notlike "*Server*") -and (passwordLastSet -ge $ComputerStaleDate)  -and (Enabled -eq $TRUE) }
                             $AllActiveComputersCount = $AllActiveWorkstations.Count
                            write-output ""`r
                            write-output "There were $AllActiveComputersCount active workstations discovered in $ComputerTargetOU ..." `r
                            write-output ""`r
                            [array]$ComputerList = $AllActiveWorkstations
                           }  ## CLOSE Switch Workstation Option

                          Server
                           {  ## OPEN Switch Server Option
                            # Gather a list of all active Servers (not including Domain Controllers) in specified OU tree including necessary attributes
                            write-output "Discovering Active Windows SERVERS in $ComputerTargetOU ..." `r
                             $AllActiveServers = Get-ADComputer  -SearchBase $ComputerTargetOU -filter {(OperatingSystem -like "*Windows*") -and (OperatingSystem -like "*Server*") -and (passwordLastSet -ge $ComputerStaleDate)  -and (Enabled -eq $TRUE)-and (PrimaryGroupID -eq 515) }
                             $AllActiveComputersCount = $AllActiveServers.Count
                            write-output "" `r
                            write-output "There were $AllActiveComputersCount Active Windows SERVERS discovered in $ComputerTargetOU ..." `r
                            write-output "" `r  
                            [array]$ComputerList = $AllActiveServers
                           }  ## CLOSE Switch Server Option
                        }  ## CLOSE Switch ComputerType  
                    ForEach ($Computer in $ComputerList)
                        {  ## OPEN Computer in ComputerList
                            $TargetComputerList += $Computer.Name
                        }  ## CLOSE Computer in ComputerList    
        }  ## CLOSE IF OUName is specified

    IF ($ConfigTarget -eq "Domain")
        {  ## OPEN IF ConfigTarget = Domain
    Switch ($ComputerType)
            # This determines what type of computer object is returned: workstation or server
            {  ## OPEN Switch ComputerType

                          Workstation
                           {  ## OPEN Switch Workstation Option
                            # Gather a list of all active workstations in specified OU tree including necessary attributes
                            write-output "Discovering active workstations in $ADDomainDNSRoot ..." `r
                             $AllActiveWorkstations = Get-ADComputer -filter {(OperatingSystem -like "*Windows*") -and (OperatingSystem -notlike "*Server*") -and (passwordLastSet -ge $ComputerStaleDate)  -and (Enabled -eq $TRUE) }
                             $AllActiveComputersCount = $AllActiveWorkstations.Count
                            write-output ""`r
                            write-output "There were $AllActiveComputersCount active workstations discovered in $ADDomainDNSRoot ..." `r
                            write-output ""`r
                            [array]$ComputerList = $AllActiveWorkstations
                           }  ## CLOSE Switch Workstation Option

                          Server
                           {  ## OPEN Switch Server Option
                            # Gather a list of all active Servers (not including Domain Controllers) in specified OU tree including necessary attributes
                            write-output "Discovering Active Windows SERVERS in $ADDomainDNSRoot ..." `r
                             $AllActiveServers = Get-ADComputer -filter {(OperatingSystem -like "*Windows*") -and (OperatingSystem -like "*Server*") -and (passwordLastSet -ge $ComputerStaleDate)  -and (Enabled -eq $TRUE)-and (PrimaryGroupID -eq 515) }
                             $AllActiveComputersCount = $AllActiveServers.Count
                            write-output "" `r
                            write-output "There were $AllActiveComputersCount Active Windows SERVERS discovered in $ADDomainDNSRoot ..." `r
                            write-output "" `r  
                            [array]$ComputerList = $AllActiveServers
                           }  ## CLOSE Switch Server Option
                        }  ## CLOSE Switch ComputerType

    ForEach ($Computer in $ComputerList)
            {  ## OPEN Computer in ComputerList
                $TargetComputerList += $Computer.Name
            }  ## CLOSE Computer in ComputerList    

        }  ## CLOSE IF ConfigTarget = Domain

      # Sort the list alphabetically
        $ComputerList = $ComputerList | sort
        $TargetComputerListCount = $TargetComputerList.Count

        # Output Computer list to ComputerWorkFile
        write-output ""`r
        write-output "Saving computer job list to computer work file..."`r
        write-output ""`r  
        $TargetComputerList | out-file $ComputerWorkFile -force