How to sort registry entries by last write time/last modified time in PowerShell

Question

I am learning PowerShell, I use PSCore7.1 on Windows 10 20H2, currently I can do this:

Get-ChildItem -Path "C:\" -Directory -Recurse -Depth 5 | Where-Object{$_.LastWriteTime.ToString("yyyy-MM-dd") -eq "2020-12-14"} | Sort-Object LastWriteTime

To recursively get subfolders within given depth (in this case 5) of a specified directory (in this case C:), then find objects modified in a given time range (in this case today or December 14, 2020), and finally sort the results by timestamp.

But when I run get-childitem to view the registry, like this:

Get-ChildItem -Path "HKLM:\SOFTWARE"

There are only two items: Name and Property, no timestamp, and in regedit.exe there is also no timestamp, so how can I sort registry keys by last modified time like the command I posted above using PowerShell?

Edit: I have read here in Super User I can export registry keys to txt files in Registry Editor to view their timestamps, though it's simple, it is irrelevant to this question as I want to sort registry keys by timestamp in console.

Re-Edit:

I have run this command:

get-childitem -path "HKLM:\"  | Get-Member

And here are the results:

   TypeName: Microsoft.Win32.RegistryKey

Name                      MemberType   Definition
----                      ----------   ----------
Close                     Method       void Close()
CreateSubKey              Method       Microsoft.Win32.RegistryKey CreateSubKey(string subkey), Microsoft.Win32.RegistryKey CreateSubKey(string subkey, bool writable…
DeleteSubKey              Method       void DeleteSubKey(string subkey), void DeleteSubKey(string subkey, bool throwOnMissingSubKey)
DeleteSubKeyTree          Method       void DeleteSubKeyTree(string subkey), void DeleteSubKeyTree(string subkey, bool throwOnMissingSubKey)
DeleteValue               Method       void DeleteValue(string name), void DeleteValue(string name, bool throwOnMissingValue)
Dispose                   Method       void Dispose(), void IDisposable.Dispose()
Equals                    Method       bool Equals(System.Object obj)
Flush                     Method       void Flush()
GetAccessControl          Method       System.Security.AccessControl.RegistrySecurity GetAccessControl(), System.Security.AccessControl.RegistrySecurity GetAccessCon…
GetHashCode               Method       int GetHashCode()
GetLifetimeService        Method       System.Object GetLifetimeService()
GetSubKeyNames            Method       string[] GetSubKeyNames()
GetType                   Method       type GetType()
GetValue                  Method       System.Object GetValue(string name), System.Object GetValue(string name, System.Object defaultValue), System.Object GetValue(s…
GetValueKind              Method       Microsoft.Win32.RegistryValueKind GetValueKind(string name)
GetValueNames             Method       string[] GetValueNames()
InitializeLifetimeService Method       System.Object InitializeLifetimeService()
OpenSubKey                Method       Microsoft.Win32.RegistryKey OpenSubKey(string name), Microsoft.Win32.RegistryKey OpenSubKey(string name, bool writable), Micro…
SetAccessControl          Method       void SetAccessControl(System.Security.AccessControl.RegistrySecurity registrySecurity)
SetValue                  Method       void SetValue(string name, System.Object value), void SetValue(string name, System.Object value, Microsoft.Win32.RegistryValue…
ToString                  Method       string ToString()
Property                  NoteProperty string[] Property=System.String[]
PSChildName               NoteProperty string PSChildName=BCD00000000
PSDrive                   NoteProperty PSDriveInfo PSDrive=HKLM
PSIsContainer             NoteProperty bool PSIsContainer=True
PSParentPath              NoteProperty string PSParentPath=Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE
PSPath                    NoteProperty string PSPath=Microsoft.PowerShell.Core\Registry::HKEY_LOCAL_MACHINE\BCD00000000
PSProvider                NoteProperty ProviderInfo PSProvider=Microsoft.PowerShell.Core\Registry
Handle                    Property     Microsoft.Win32.SafeHandles.SafeRegistryHandle Handle {get;}
Name                      Property     string Name {get;}
SubKeyCount               Property     int SubKeyCount {get;}
ValueCount                Property     int ValueCount {get;}
View                      Property     Microsoft.Win32.RegistryView View {get;}

As you can see, there is no timestamp...

Cite: Is there any way to view dates of changes to Windows registry keys/values?

Proof:

Key Name:          HKEY_CLASSES_ROOT\._bsln140
Class Name:        <NO CLASS>
Last Write Time:   2020-12-11 - 14:54
Value 0
  Name:            <NO NAME>
  Type:            REG_SZ
  Data:            VisualStudio.Launcher._bsln140

Answer 1

Unfortunately, this can get complicated due to how windows accesses registry key info, but it is possible. Below is a series of tutorials by Dr Scripto on the Microsoft devblog:

• use powershell to access registry last modified time stamp covers how to, in powershell, use the Win32 function RegQueryInfoKey to get timestamps.
• reusing powershell registry time stamp code covers creating a reusable tool by wrapping that code in a Windows PowerShell function.
• leverage registry key time stamps via powershell covers some real-world usage.

The final product is going to look like this, saved as Add-RegKeyLastWriteTime.ps1:

#requires -version 3.0

function Add-RegKeyLastWriteTime {
[CmdletBinding()]
param(
    [Parameter(Mandatory, ParameterSetName="ByKey", Position=0, ValueFromPipeline)]
    # Registry key object returned from Get-ChildItem or Get-Item
    [Microsoft.Win32.RegistryKey] $RegistryKey,
    [Parameter(Mandatory, ParameterSetName="ByPath", Position=0)]
    # Path to a registry key
    [string] $Path
)

 begin {
    # Define the namespace (string array creates nested namespace):
    $Namespace = "HeyScriptingGuy"

    # Make sure type is loaded (this will only get loaded on first run):
    Add-Type @"
        using System;
        using System.Text;
        using System.Runtime.InteropServices;

        $($Namespace | ForEach-Object {
            "namespace $_ {"
        })
            public class advapi32 {
                [DllImport("advapi32.dll", CharSet = CharSet.Auto)]
                public static extern Int32 RegQueryInfoKey(
                    Microsoft.Win32.SafeHandles.SafeRegistryHandle hKey,
                    StringBuilder lpClass,
                    [In, Out] ref UInt32 lpcbClass,
                    UInt32 lpReserved,
                    out UInt32 lpcSubKeys,
                    out UInt32 lpcbMaxSubKeyLen,
                    out UInt32 lpcbMaxClassLen,
                    out UInt32 lpcValues,
                    out UInt32 lpcbMaxValueNameLen,
                    out UInt32 lpcbMaxValueLen,
                    out UInt32 lpcbSecurityDescriptor,
                    out System.Runtime.InteropServices.ComTypes.FILETIME lpftLastWriteTime
                );
            }
        $($Namespace | ForEach-Object { "}" })
"@
   
    # Get a shortcut to the type:   
    $RegTools = ("{0}.advapi32" -f ($Namespace -join ".")) -as [type]
}
 process {
    switch ($PSCmdlet.ParameterSetName) {
        "ByKey" {
            # Already have the key, no more work to be done 🙂
        }
        "ByPath" {
            # We need a RegistryKey object (Get-Item should return that)
            $Item = Get-Item -Path $Path -ErrorAction Stop
 
            # Make sure this is of type [Microsoft.Win32.RegistryKey]
            if ($Item -isnot [Microsoft.Win32.RegistryKey]) {
                throw "'$Path' is not a path to a registry key!"
            }
            $RegistryKey = $Item
        }
    }
 
    # Initialize variables that will be populated:
    $ClassLength = 255 # Buffer size (class name is rarely used, and when it is, I've never seen
                        # it more than 8 characters. Buffer can be increased here, though.
    $ClassName = New-Object System.Text.StringBuilder $ClassLength  # Will hold the class name
    $LastWriteTime = New-Object System.Runtime.InteropServices.ComTypes.FILETIME 
           
    switch ($RegTools::RegQueryInfoKey($RegistryKey.Handle,
        $ClassName,
        [ref] $ClassLength,
        $null,  # Reserved
        [ref] $null, # SubKeyCount
        [ref] $null, # MaxSubKeyNameLength
        [ref] $null, # MaxClassLength
        [ref] $null, # ValueCount
        [ref] $null, # MaxValueNameLength
        [ref] $null, # MaxValueValueLength
        [ref] $null, # SecurityDescriptorSize
        [ref] $LastWriteTime
    )) {
         0 { # Success
            # Convert to DateTime object:
            $UnsignedLow = [System.BitConverter]::ToUInt32([System.BitConverter]::GetBytes($LastWriteTime.dwLowDateTime), 0)
            $UnsignedHigh = [System.BitConverter]::ToUInt32([System.BitConverter]::GetBytes($LastWriteTime.dwHighDateTime), 0)
            # Shift high part so it is most significant 32 bits, then copy low part into 64-bit int:
            $FileTimeInt64 = ([Int64] $UnsignedHigh -shl 32) -bor $UnsignedLow
            # Create datetime object
            $LastWriteTime = [datetime]::FromFileTime($FileTimeInt64)
 
            # Add properties to object and output them to pipeline
            $RegistryKey | Add-Member -NotePropertyMembers @{
                LastWriteTime = $LastWriteTime
                ClassName = $ClassName.ToString()
            } -PassThru -Force
        }
        122  { # ERROR_INSUFFICIENT_BUFFER (0x7a)
            throw "Class name buffer too small"
            # function could be recalled with a larger buffer, but for
            # now, just exit
        }
        default {
            throw "Unknown error encountered (error code $_)"
        }
    }
}
}

Then finally, a usage example:

Get-ChildItem HKCU:\ | Add-RegKeyLastWriteTime | Select Name,LastWriteTime
'
Name                                                         LastWriteTime         
----                                                         -------------         
HKEY_CURRENT_USER\AppEvents                                  7/6/2020 8:56:11 AM   
HKEY_CURRENT_USER\Console                                    7/6/2020 8:56:11 AM   
HKEY_CURRENT_USER\Control Panel                              7/6/2020 1:04:53 PM  
'