function Get-Cert {
<#

.SYNOPSIS

Prints out the list of certs in stores specified by the global 'certDirectories' variable. Adds handy Properties to the X509Certificates returned.
Including: Expiration, SubjectAlternateNames, Path, FileName



.DESCRIPTION


.PARAMETER filter

A filter that gets applied across all relevant cert info: Thumbprint, Subject, SerialNumber, etc...

.PARAMETER Expiration
A switch that will display the certs sorted by expiration. Equivalent to 'lscert | sort expiration | ft expiration,thumbprint,subject'

.PARAMETER thumbprint

Filter used against the thumbprints

.PARAMETER subject

Filter used against the subjects

.PARAMETER altName

Filter used against the subject alternative names

.PARAMETER certDirectoryOverride

An override for specific cert stores to search

.PARAMETER localFolders

A local folder cotaining *.cer files that will also be loaded. Will recursively search

.PARAMETER private

Filters certs that contain private keys


.EXAMPLE

Find a cert matching a generic filter

Get-Cert microsoft

.EXAMPLE

Find all installed certs and all certs in a directory matching the filter and then output their path

Get-Cert contoso -localFolders C:\my\local\certs\ | ft path


.EXAMPLE

Find a cert matching a specific thumbprint

Get-cert -thumbprintFilter 1342


.EXAMPLE

Get all certs with private keys

Get-Cert -privateKey

#>

  param (
    [string]$filter,
    [string]$thumbprint,
    [string]$subject,
    [string]$altName,
    [string]$serialNumber,
    [switch]$expiration,
    [switch]$privateKey,
    [string[]]$certDirectoryOverride,
    [string[]]$localFolders
    )
  $certDirectories  = "cert:\CurrentUser\My", "cert:\LocalMachine\My"

  # Set the cert store to list from
  $certStores = $certDirectories
  if ($certDirectoryOverride -ne $null) {
    $certStores = $certDirectoryOverride
  }

  $items = @()
  # get all certs from the stores
  foreach ($store in $certStores) {
    $items += ls $store
  }

  if ($localFolders) {
    foreach ($folder in $localFolders) {
      $localCertPaths = ls -path $folder -i *cer -rec
      foreach ($certPath in $localCertPaths) {
        $fullName = $certPath.FullName
        $directoryName = $certPath.DirectoryName
        $cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($certPath)
        add-member -InputObject $cert -MemberType NoteProperty -Name PSParentPath -Value $directoryName -ErrorAction SilentlyContinue
        add-member -InputObject $cert -MemberType NoteProperty -Name Path -Value $fullName
        add-member -InputObject $cert -MemberType NoteProperty -Name FileName -Value $fileName

        $items += $cert;
      }
    }
  }

  # add handy expiration property
  $items | %{
    add-member -InputObject $_ -MemberType ScriptProperty -Name Expiration -Value {[DateTime]$this.GetExpirationDateString()} -ErrorAction SilentlyContinue
    add-member -InputObject $_ -MemberType AliasProperty -Name Path -Value PSPath -ErrorAction SilentlyContinue
    add-member -InputObject $_ -MemberType AliasProperty -Name FileName -Value PSPath -ErrorAction SilentlyContinue

    add-member -InputObject $_ -MemberType ScriptProperty -Name SubjectAlternateNames -ErrorAction SilentlyContinue -Value {
      return ($this.Extensions | Where-Object {$_.Oid.FriendlyName -eq "subject alternative name"}).Format(1).Replace("`r`n",", ").Replace("DNS Name=","")
    }
    add-member -InputObject $_ -MemberType AliasProperty -Name AlternateNames -Value SubjectAlternateNames -ErrorAction SilentlyContinue
    add-member -InputObject $_ -MemberType AliasProperty -Name AlternativeNames -Value SubjectAlternateNames -ErrorAction SilentlyContinue
    add-member -InputObject $_ -MemberType AliasProperty -Name SubjectAlternativeNames -Value SubjectAlternateNames -ErrorAction SilentlyContinue
    add-member -InputObject $_ -MemberType AliasProperty -Name SubjectAltNames -Value SubjectAlternateNames -ErrorAction SilentlyContinue
    add-member -InputObject $_ -MemberType AliasProperty -Name AltNames -Value SubjectAlternateNames -ErrorAction SilentlyContinue
  }

  # filter all the certs
  if ($filter -ne $null) {
    $items = $items | where-object {
      ($_.Thumbprint -match $filter) -or
      ($_.Subject -match $filter) -or
      ($_.SerialNumber -match $filter) -or
      ($_.SubjectAlternateName -match $filter)
      }
  }
  if ($thumbprint -ne $null) {
    $items = $items | where {$_.Thumbprint -match $thumbprint}
  }
  if ($subject -ne $null) {
    $items = $items | where {$_.Subject -match $subject}
  }
  if ($altName -ne $null) {
    $items = $items | where {$_.SubjectAlternateNames -match $altName}
  }
  if ($serialNumber -ne $null) {
    $items = $items | where {$_.SerialNumber -match $serialNumber}
  }
  if ($privateKey) {
    $items = $items | where {$_.PrivateKey -ne $null}
  }

  if ($expiration) {
    return $items | sort expiration | ft expiration, thumbprint, subject
  }

  return $items
}

new-alias lscert Get-Cert -ErrorAction SilentlyContinue
new-alias dircert Get-Cert -ErrorAction SilentlyContinue