# encoding: ascii
# api: powershell
# title: Compare Reg Keys
# description: Two functions Get-AllRegkey and Compare-AllRegKey which will recursivly retrieve a key’s properties and subkeys, and their properties and subkeys, as an array of objects, across multiple computers. The Compare-AllRegKey function uses Compare-Object to compare the arrays returned from each computer to an array returned from a specified reference computer.
# version: 0.1
# type: script
# author: whertzing56
# license: CC0
# function: Get-AllRegKey
# x-poshcode-id: 2850
# x-archived: 2016-01-21T17:40:01
# x-published: 2012-07-26T21:09:00
#
#
<#
.SYNOPSIS
Compares Registry Key Properties and subkeys across multiple computers
.DESCRIPTION
The function Get-AllRegKey will recurse down from a given key, returning an array having
the key's properties, subkeys, and their properties and subkeys.
Provide Get-AllRegKey a list of computernames, and it will remote to those computers
and return the properties, etc. of the same key on the remote computer
Provide function Compare-AllRegKey with the name of the reference computer, a list of
two or more computer names, and it will call Get-AllRegKey to retrieve the key
information from all the listed computers, then use Compare-Object to return
just the differences.
If you want more control over the Compare-Object step, you should modify the
function (suggestions welcome for an efficient/concise way to add Compare-Object
parameters to the Compare-AllRegKey function)
.PARAMETER ComputerNames
In the Get-AllRegKey function this is a single computer name or an array of computer names
In the Compare-AllRegKey function, this must be an array of at least two computer names
.PARAMETER RegKey
a single registry key/hive from which recursion starts, using the Registry Provider syntax
The value defaults to the current-scoped variable $DefaultRegistryKey
.PARAMETER -ReferenceObject
Applies only to the Compare-AllRegKey function, this parameter identifies the computer
against which the other computers are compared. This string must be one of the computer
names found in the ComputerNames parameter.
.EXAMPLE
C:\PS> Get-AllRegKey
.EXAMPLE
C:\PS> Get-AllRegKey -RegistryKey 'HKLM:\SOFTWARE\Microsoft\PowerShell'
.EXAMPLE
C:\PS> Get-AllRegKey -ComputerNames @('localhost','RemoteCN')
.EXAMPLE
C:\PS> Get-AllRegKey -ComputerNames @('localhost','Computer1','Computer2')
.EXAMPLE
C:\PS> Get-AllRegKey localhost 'HKLM:\SOFTWARE\Microsoft\PowerShell'
.EXAMPLE
C:\PS> Compare-AllRegKey -ComputerNames @('localhost','RemoteCN')
.EXAMPLE
C:\PS> Compare-AllRegKey -ComputerNames @('CN1','CN2') -ReferenceObject CN2
#>
################################################################################
# Default values for the Registry Key and the list of computernames
$DefaultRegistryKey='HKLM:\SOFTWARE\Microsoft\PowerShell'
$computerNames= @('localhost','ncat099')
################################################################################
# The scriptblock that does the actual work of creating an object representing a
# registry key and all it's properties and subkeys and their properties. No Defaults
# This is recursive and remoteable
$_getRegKeySB = {Param($RegistryHive)
# Create a local named function
function _getRegKey {
Param($RegistryHive)
# $data is an array, local to each loop of the recursion
# initialize it with the name of the hive/key
$data=@($RegistryHive)
# Get the hive/keys properties, excluding the ones added by PS
$props = Get-ItemProperty -Path $RegistryHive |
Select * -Exclude PS*Path,PSChildName,PSDrive,PSProvider
# if $props is empty, piping it to get-member produces an error message
# so test it for non-null first
if ($props) {
$props = $props | get-member -memberType NoteProperty
# prepend each property with the full name of the key, and add it to $data
foreach ($p in $props) {$data+=("$RegistryHive`:"+$p.Definition)}
}
# recursivly call the same algorithm for any subkeys of the hive/key
foreach ($sk in (get-item $RegistryHive).GetSubKeyNames()) {
# if there are any subkeys, append their data to the current data.
# Use the full name of the key
$data += (&_getRegKey (($RegistryHive)+'\'+ $sk))
}
# the local named function's output is the array representation of the hive/key
$data
}
# Call the local named function
&_getRegKey $RegistryHive
}
################################################################################
# Across all computers, get the key and subkeys from the registry
# returns a hash of array objects, keyed by computer name
function Get-AllRegKey {
Param (
# Single computer name or an array of computer names.
# Defaults to the "current scoped variable by the same name"
$computerNames = $computerNames
# A valid key
,$RegistryKey = $DefaultRegistryKey
)
# create the empty hash
$AllRegKey = @{}
# iterate over each computer name
foreach ($cn in $computerNames) {
switch ($cn) {
# If the computer name is localhost, or the same name as hostname
# use the Call operator to call the scriptblock, and assign the array returned
# to the hash using the current computername as the key
{$_ -match "localhost|" + (hostname)} {
$AllRegKey.$cn = &$_getRegKeySB $RegistryKey
break
}
# for all other computer names, execute the command remotely using invoke-command
default {
# pass the scriptblock to the remote computers
# assign the array returned to the hash using the current computername as the key
$AllRegKey.$cn = (invoke-command -Scriptblock $_getRegKeySB `
-ArgumentList $RegistryKey -computername "$cn")
}
}
}
#return the hash of arrays
$AllRegKey
}
################################################################################
# Across all computers, get the key and subkeys from the registry
# returns a hash of array objects, keyed by computer name
function Compare-AllRegKey {
Param (
# Must be an array, with 2 or more members;
# defaults to the "current scoped variable by the same name"
$computerNames = $computerNames
# A valid key
,$RegistryKey = $DefaultRegistryKey
# The name of the computer to use as the reference
,$ReferenceObject
)
Begin {
# If the argument for $ReferenceObject is null, then default
# to the first element of $computerNames
if (!$ReferenceObject) {$ReferenceObject =$computerNames[0]}
else {
# Validate that the $referenceObject is an element of $computerNames
if (!($computerNames -contains $ReferenceObject)) {
throw ("{0} is not a member of the list {1}" -f $ReferenceObject, `
($computerNames -join ','))}
}
# Get the Registry Key data for all computers
$AllRegKey = Get-AllRegKey $computerNames $RegistryKey
}
Process {
# Iterate over the computernames, excluding the $ReferenceObject
$diff = @{};
foreach ($cn in $computerNames | Where {$cn -ne $ReferenceObject}) {
# compare $ReferenceObject to the remaining objects, accumulate into $diff
$diff.$cn = Compare-Object -ReferenceObject $AllRegKey.$ReferenceObject `
$AllRegKey.$cn | Where-Object { `
($_.SideIndicator -eq '=>') -or ($_.SideIndicator -eq '<=') }
}
# Return the difference hash
$diff
}
}
# The following lines will compare the default registry key
# across the default array of computernames
Compare-AllRegKey