Public/Get-RegString.ps1

function Get-RegString
{

    <#
    .SYNOPSIS
        Retrieves a registry string (REG_SZ) value from local or remote computers.
 
    .DESCRIPTION
        Use Get-RegString to retrieve a registry string (REG_SZ) value from local or remote computers.
            
    .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.
            
    .EXAMPLE
        Get-RegString -Hive LocalMachine -Key SOFTWARE\Microsoft\DataAccess -Value FullInstallVer
 
        ComputerName Hive Key Value Data Type
        ------------ ---- --- ----- ---- ----
        COMPUTER1 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 6.1.7600.16385 String
         
         
        Description
        -----------
        The command gets the installed version of Microsoft Data Access Components (MDAC) from the local computer.
        The name of ComputerName parameter, which is optional, is omitted.
         
    .EXAMPLE
        "SERVER1","SERVER2","SERVER3" | Get-RegString -Key SOFTWARE\Microsoft\DataAccess -Value FullInstallVer -Ping
         
        ComputerName Hive Key Value Data Type
        ------------ ---- --- ----- ---- ----
        SERVER1 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 2.82.3959.0 String
        SERVER2 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 2.82.3959.0 String
        SERVER3 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 2.82.1830.0 String
 
        Description
        -----------
        The command gets the installed version of Microsoft Data Access Components (MDAC) from remote computers.
        When the Switch parameter Ping is specified the command issues a ping test to each computer.
        If the computer is not responding to the ping request a warning message is written to the console and the computer is not processed.
 
    .EXAMPLE
        Get-Content servers.txt | Get-RegString -Key SOFTWARE\Microsoft\DataAccess -Value FullInstallVer
         
        ComputerName Hive Key Value Data Type
        ------------ ---- --- ----- ---- ----
        SERVER1 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 2.82.3959.0 String
        SERVER2 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 2.82.3959.0 String
        SERVER3 LocalMachine SOFTWARE\Microsoft\DataAccess FullInstallVer 2.82.1830.0 String
 
        Description
        -----------
        The command uses the Get-Content cmdlet to get the server names from a text file.
 
    .EXAMPLE
        Get-RegString -Hive LocalMachine -Key SOFTWARE\Microsoft\DataAccess -Value FullInstallVer | Test-RegValue -ComputerName SERVER1,SERVER2 -Ping
        True
        True
 
        Description
        -----------
        This command gets the installed version of Microsoft Data Access Components (MDAC) from the local computer.
        The output is piped to the Test-RegValue function to check if the value exists on two remote computers.
        When the Switch parameter Ping is specified the command issues a ping test to each computer.
        If the computer is not responding to the ping request a warning message is written to the console and the computer is not processed.
 
    .OUTPUTS
        PSFanatic.Registry.RegistryValue (PSCustomObject)
 
    .LINK
        Set-RegString
        Get-RegValue
        Remove-RegValue
        Test-RegValue
    #>

    
    [OutputType('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 get."
        )]
        [string]$Value,
        
        [switch]$Ping
    ) 
    

    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."
                }                
                
                Write-Verbose "Get value name : [$Value]"
                $rv = $subKey.GetValue($Value,-1)
                
                if($rv -eq -1)
                {
                    Write-Error "Cannot find value [$Value] because it does not exist."
                }
                else
                {
                    Write-Verbose "Create PSFanatic registry value custom object."
                    
                    $pso = New-Object PSObject -Property @{
                        ComputerName=$c
                        Hive=$Hive
                        Value=$Value
                        Key=$Key
                        Data=$rv
                        Type=$subKey.GetValueKind($Value)
                    }

                    Write-Verbose "Adding format type name to custom object."
                    $pso.PSTypeNames.Clear()
                    $pso.PSTypeNames.Add('PSFanatic.Registry.RegistryValue')
                    $pso
                }
                
                Write-Verbose "Closing remote registry connection on: [$c]."
                $subKey.close()
            }
            catch
            {
                Write-Error $_
            }
        } 
        
        Write-Verbose "Exit process block..."
    }
}