Public/Test-RegValue.ps1

function Test-RegValue
{

    <#
    .SYNOPSIS
           Determines if a registry value exists.
 
    .DESCRIPTION
           Use Test-RegValue to determine if the registry value exists.
            
    .PARAMETER ComputerName
            An array of computer names. The default is the local computer.
 
    .PARAMETER Hive
           The HKEY to open, from the RegistryHive enumeration. The default is 'LocalMachine'.
           Possible values:
            
        - ClassesRoot
        - CurrentUser
        - LocalMachine
        - Users
        - PerformanceData
        - CurrentConfig
        - DynData
 
    .PARAMETER Key
           The path of the registry key to open.
 
    .PARAMETER Value
           The name of the registry value.
 
    .PARAMETER Ping
           Use ping to test if the machine is available before connecting to it.
           If the machine is not responding to the test a warning message is output.
 
    .PARAMETER PassThru
           Passes the registry value, if found.
               
    .EXAMPLE
        $Key = "SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine"
        Test-RegValue -ComputerName SERVER1 -Key $Key -Value PowerShellVersion
         
        True
 
 
        Description
        -----------
        The command checks if the PowerShellVersion value exists on SERVER1.
        If the Value was found the result is True, else False.
     
    .EXAMPLE
        Get-Content servers.txt | Test-RegValue -Key $Key -PassThru
 
        ComputerName Hive Key Value Data Type
        ------------ ---- --- ----- ---- ----
        SERVER1 LocalMachine SOFTWARE\Microsof... PowerShellVersion 1.0 String
        SERVER2 LocalMachine SOFTWARE\Microsof... PowerShellVersion 1.0 String
        SERVER3 LocalMachine SOFTWARE\Microsof... PowerShellVersion 1.0 String
 
        Description
        -----------
        The command uses the Get-Content cmdlet to get the server names from a text file. The names are piped into
        Test-RegValue. If the Value was found and PassThru is specidied, the result is the registry value custom object.
 
    .OUTPUTS
        System.Boolean
        PSFanatic.Registry.RegistryValue (PSCustomObject)
 
    .NOTES
        Author: Shay Levy
        Blog : http://blogs.microsoft.co.il/blogs/ScriptFanatic/
         
    .LINK
        http://code.msdn.microsoft.com/PSRemoteRegistry
 
    .LINK
        Get-RegValue
        Remove-RegValue
         
    #>

    

    [OutputType('System.Boolean','PSFanatic.Registry.RegistryValue')]
    [CmdletBinding(DefaultParameterSetName="__AllParameterSets")]
    
    param( 
        [Parameter(
            Position=0,
            ValueFromPipeline=$true,
            ValueFromPipelineByPropertyName=$true,
            HelpMessage="An array of computer names. The default is the local computer."
        )]        
        [Alias("CN","__SERVER","IPAddress")]
        [string[]]$ComputerName="",        
        
        [Parameter(
            Position=1,
            ValueFromPipelineByPropertyName=$true,
            HelpMessage="The HKEY to open, from the RegistryHive enumeration. The default is 'LocalMachine'."
        )]
        [ValidateSet("ClassesRoot","CurrentUser","LocalMachine","Users","PerformanceData","CurrentConfig","DynData")]
        [string]$Hive="LocalMachine",
        
        [Parameter(
            Mandatory=$true,
            Position=2,
            ValueFromPipelineByPropertyName=$true,
            HelpMessage="The path of the subkey to open."
        )]
        [string]$Key,

        [Parameter(
            Mandatory=$true,
            Position=3,
            ValueFromPipelineByPropertyName=$true,
            HelpMessage="The name of the value to test."
        )]
        [string]$Value,
        
        [switch]$Ping,
        
        [switch]$PassThru
    ) 
    

    process
    {
            
            Write-Verbose "Enter process block..."
        
        foreach($c in $ComputerName)
        {    
            try
            {                
                if($c -eq "")
                {
                    $c=$env:COMPUTERNAME
                    Write-Verbose "Parameter [ComputerName] is not presnet, setting its value to local computer name: [$c]."
                    
                }
                
                if($Ping)
                {
                    Write-Verbose "Parameter [Ping] is presnet, initiating Ping test"
                    
                    if( !(Test-Connection -ComputerName $c -Count 1 -Quiet))
                    {
                        Write-Warning "[$c] doesn't respond to ping."
                        return
                    }
                }

                
                Write-Verbose "Starting remote registry connection against: [$c]."
                Write-Verbose "Registry Hive is: [$Hive]."
                $reg = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey([Microsoft.Win32.RegistryHive]$Hive,$c)        
                
                Write-Verbose "Open remote subkey: [$Key]"
                $subKey = $reg.OpenSubKey($key)

                if(!$subKey)
                {
                    Throw "Key '$Key' doesn't exist."
                }
                
                if($Value -ne '(default)')
                {
                    $rv=$subKey.GetValue($Value,-1)
    
                    if($rv -eq -1)
                    {
                        $false
                    }
                    else
                    {
                        if($PassThru)
                        {
                            Write-Verbose "Parameter [PassThru] is presnet, creating PSFanatic registry custom objects."
                            Write-Verbose "Create PSFanatic registry value custom object."

                            $pso = New-Object PSObject -Property @{
                                ComputerName=$c
                                Hive=$Hive
                                Value=$Value
                                Key=$Key
                                Data=$subKey.GetValue($Value)
                                Type=$subKey.GetValueKind($Value)
                            }

                            Write-Verbose "Adding format type name to custom object."
                            $pso.PSTypeNames.Clear()
                            $pso.PSTypeNames.Add('PSFanatic.Registry.RegistryValue')
                            $pso
                        }
                        else
                        {
                            $true
                        }
                    }
                }

                Write-Verbose "Closing remote registry connection on: [$c]."
                $subKey.close()
            }
            catch
            {
                #Write-Error $_
                $false
            }
        } 
        
        Write-Verbose "Exit process block..."
    }
}