#requires -version 3.0


Function Get-CIMFile {

<#
.Synopsis
Get a file object using CIM.
.Description
This command uses the Get-CIMInstance and the CIM_DataFile class to find a 
file or files on a computer. The command by default searches drive C: on the 
local computer for the specified file. The wildcard character (*) is permitted 
anywhere in the filename. 

You can search one or more remote computers by computername or CIM sessions.

.Parameter Name
The name of the file to find. Wildcards (*) in the name are permitted but they
will make the search run a little longer.
.Parameter Drive
The name of the drive to search. The default is C:. You do not need to include
the trailing \.
.Parameter Computername
The name of the computer to search. The default is the local computer. 
.Parameter CimSession
Connect to remote computers via a Cimsession object.
.Example
PS C:\> Get-Cimfile hidden.txt
.Example
PS C:\> Get-Cimfile myapp.dll -comp $computers 
.Example
PS C:\> $sess = New-CimSession $computers
PS C:\> Get-Cimfile myapp.dll -cimsession $sess | Select PSComputername,Name,Filesize
.Notes
Version     : 3.0
Last Updated: 02/06/2013
Author      : Jeffery Hicks (@JeffHicks)

Read PowerShell:
Learn Windows PowerShell 3 in a Month of Lunches
Learn PowerShell Toolmaking in a Month of Lunches
PowerShell in Depth: An Administrator's Guide

  ****************************************************************
  * DO NOT USE IN A PRODUCTION ENVIRONMENT UNTIL YOU HAVE TESTED *
  * THOROUGHLY IN A LAB ENVIRONMENT. USE AT YOUR OWN RISK.  IF   *
  * YOU DO NOT UNDERSTAND WHAT THIS SCRIPT DOES OR HOW IT WORKS, *
  * DO NOT USE IT OUTSIDE OF A SECURE, TEST SETTING.             *
  ****************************************************************
.Link
http://jdhitsolutions.com/blog/2013/02/find-files-with-powershell-3-0/
.Link
Get-CIMInstance
New-CimSession
.Inputs
String
.Outputs
Microsoft.Management.Infrastructure.CimInstance#root\cimv2\CIM_DataFile
#>

[cmdletbinding(DefaultParameterSetName="Computername")]

Param(
[Parameter(Position=0,Mandatory=$True,HelpMessage="What is the name of the file?")]
[ValidateNotNullorEmpty()]
[alias("file")]
[string]$Name,
[ValidatePattern("^[a-zA-Z]:$")]
[string]$Drive="C:",
[Parameter(ParameterSetName="Computername")]
[ValidateNotNullorEmpty()]
[string[]]$Computername=$env:computername,
[Parameter(ParameterSetName="CIMSession")]
[ValidateNotNullorEmpty()]
[Microsoft.Management.Infrastructure.CimSession[]]$CimSession
)

Write-Verbose "Starting $($MyInvocation.MyCommand)"
Write-Verbose "Parameter set = $($PSCmdlet.ParameterSetName)"

#create a hashtable of parameter values that can be splatted to Get-CimInstance
$paramHash=@{Classname="CIM_DATAFILE"}

Write-Verbose "Searching for $filename on drive $drive"
if ($pscmdlet.ParameterSetName -eq "Computername") {
    Write-Verbose "...on $computername"
    $paramHash.Add("Computername",$computername)
}
elseif ($pscmdlet.ParameterSetName -eq "CimSession")  {
    Write-Verbose "...on $Cimsession"
    $paramHash.Add("CimSession",$cimSession)
}
else {
    #this should never happen
    Write-Verbose "No computername or cimsession specified. Defaulting to local host"
    #bail out of the function
    Return
}

#define default operators
$fileOp="="
$extOp="="

<#
Normally you might think to simply split the name on the . character. But
you might have a filename like myfile.v2.dll so that won't work. In a case 
like this the extension would be everything after the last . and the filename
everything before.

So instead I'll use the substring method to "split" the filename string.
#>

#get the index of the last .
$index = $name.LastIndexOf(".")

#it is possible the filename doesn't have an extension
if ($index -gt 0) {
    #get the first part of the name
    $filename=$Name.Substring(0,$index)
    #get the last part of the name
    $extension=$name.Substring($index+1)
}
else {
    $filename=$Name
    #will need to use wildcard search for filename when extension is empty
    $fileop="LIKE"
    $extension=$null
}
#if there is * in the filename or extension, replace it with %
#and change the comparison operator for the WMI query
if ($filename -match "\*" ) { 
    Write-Verbose "Wildcard search on filename"
    $filename = $filename.Replace("*","%")
    $fileOp="LIKE"
}

if ($extension -match "\*") {
    Write-Verbose "Wildcard search on extension"
    $extension = $extension.Replace("*","%")
    $extOp="LIKE"
}

$filter = "Filename $fileOp '$filename' AND extension $extOp '$extension' AND Drive='$drive'"
Write-Verbose $filter

#add the filter to the hashtable
$paramHash.Add("Filter",$filter)

#invoke the command
Write-Verbose "Parameter Hash $($paramHash| out-String)"

#let's time how long it took
$start=Get-Date  

Get-CimInstance @paramhash

$end=Get-Date
Write-Verbose "Search completed in $($end-$start)"
Write-Verbose "Ending $($MyInvocation.MyCommand)"

} #end Get-CIMFile