powershell binary file comparison

Question

All, There is a application which generates it's export dumps.I need to write a script that will compare the previous days dump against the latest and if there are differences among them i have to some basic manipulations of moving and deleting sort of stuff. I have tried finding a suitable way of doing it and the method i tried was : $var_com=diff (get-content D:\local\prodexport2 -encoding Byte) (get-content D:\local\prodexport2 -encoding Byte) I tried the Compare-Object cmdlet as well. I notice a very high memory usage and eventually i get a message System.OutOfMemoryException after few minutes. Has one of you done something similer ?. Some thoughts please. There was a thread which mentioned about a has comparison which i have no idea as to how to go about. Thanks in advance folks Osp

Answer 1

With PowerShell 4 you can use native commandlets to do this:

function CompareFiles {
    param(
    [string]$Filepath1,
    [string]$Filepath2
    )
    if ((Get-FileHash $Filepath1).Hash -eq (Get-FileHash $Filepath2).Hash) {
        Write-Host 'Files Match' -ForegroundColor Green
    } else {
        Write-Host 'Files do not match' -ForegroundColor Red
    }
}

PS C:> CompareFiles .\20131104.csv .\20131104-copy.csv

Files Match

PS C:> CompareFiles .\20131104.csv .\20131107.csv

Files do not match

You could easily modify the above function to return a $true or $false value if you want to use this programmatically on a large scale

---

EDIT

After seeing this answer, I just wanted to supply larger scale version that simply returns true or false:

function CompareFiles 
{
    param
    (
        [parameter(
            Mandatory = $true,
            HelpMessage = "Specifies the 1st file to compare. Make sure it's an absolute path with the file name and its extension."
        )]
        [string]
        $file1,

        [parameter(
            Mandatory = $true,
            HelpMessage = "Specifies the 2nd file to compare. Make sure it's an absolute path with the file name and its extension."
        )]
        [string]
        $file2
    )

    ( Get-FileHash $file1 ).Hash -eq ( Get-FileHash $file2 ).Hash
}

Answer 2

if ( (Get-FileHash c:\testfiles\testfile1.txt).Hash -eq (Get-FileHash c:\testfiles\testfile2.txt).Hash ) {
   Write-Output "Files match"
} else {
   Write-Output "Files do not match"
}