How can I compare the content of 3 directories in powershell - powershell

Question

After looking into this for a while, I've found a lot of people trying to do the same thing but I haven't yet been able to find a complete answer so I'm hoping someone can help us!
What I would like to do is give 2 directories, A and B, and compare everything inside A to everything inside B and if there are any files or folders in B that are not in A then generate an output file detailing the path to the item that is in B and not A. From Here, Id like to use the list of items and say if any of the items in these paths contain something different to the files in 2 directories (the names will be the same so documents\folder\B.txt contains something different to desktop\folder\B.txt) generate another list showing what is different or showing the file path to items that are different if I cant show the text that is different.
I've looked into doing this with .hash but I'm not sure if that's to best way to go about it? something like:
$SourceDocs = Get-ChildItem –Path C:\Documents1 | foreach {Get-FileHash –Path $_.FullName} $DestDocs = Get-ChildItem –Path C:\Documents2 | foreach {Get-FileHash –Path $_.FullName}
In terms of what I have for the physical comparison, I originally was trying to do a 3-way comparison so the code below isn't accurate but its all I've got as yet.
$folderA = 'C:\Users\USERNAME\Desktop\Folder A'
$folderB = 'C:\Users\USERNAME\Desktop\Folder B'
$folderC = 'C:\Users\USERNAME\Desktop\Folder C'
$AChild = Get-ChildItem $folderA -Recurse
$BChild = Get-ChildItem $folderB -Recurse
$CChild = Get-ChildItem $folderC -Recurse
Compare-Object -ReferenceObject $AChild -DifferenceObject $BChild, $CChildcode
After looking into this further, Ive found out it might be better to use 3.0 rather than 2.0 so I can use -Dir more efficiently.
Any questions, let me know.
Any help greatly appreciated.

Answer 1

This is answer to what you want:
What I would like to do is give 2 directories, A and B, and compare everything inside A to everything inside B and if there are any files or folders in B that are not in A then generate an output file detailing the path to the item that is in B and not A.
$folder1 = "C:\Users\USERNAME\Desktop\Folder A"
$folder2 = "C:\Users\USERNAME\Desktop\Folder B"
# Get all files under $folder1, filter out directories
$firstFolder = Get-ChildItem -Recurse $folder1 | Where-Object { -not $_.PsIsContainer }
$failedCount = 0
$i = 0
$totalCount = $firstFolder.Count
$firstFolder | ForEach-Object {
$i = $i + 1
Write-Progress -Activity "Searching Files" -status "Searching File $i of $totalCount" -percentComplete ($i / $firstFolder.Count * 100)
# Check if the file, from $folder1, exists with the same path under $folder2
If ( Test-Path ( $_.FullName.Replace($folder1, $folder2) ) ) {
# Compare the contents of the two files...
If ( Compare-Object (Get-Content $_.FullName) (Get-Content $_.FullName.Replace($folder1, $folder2) ) ) {
# List the paths of the files containing diffs
$fileSuffix = $_.FullName.TrimStart($folder1)
$failedCount = $failedCount + 1
Write-Host "$fileSuffix is on each server, but does not match"
}
}
else
{
$fileSuffix = $_.FullName.TrimStart($folder1)
$failedCount = $failedCount + 1
Write-Host "$fileSuffix is only in folder 1"
$fileSuffix | Out-File "$env:userprofile\desktop\folder1.txt" -Append
}
}
$secondFolder = Get-ChildItem -Recurse $folder2 | Where-Object { -not $_.PsIsContainer }
$i = 0
$totalCount = $secondFolder.Count
$secondFolder | ForEach-Object {
$i = $i + 1
Write-Progress -Activity "Searching for files only on second folder" -status "Searching File $i of $totalCount" -percentComplete ($i / $secondFolder.Count * 100)
# Check if the file, from $folder2, exists with the same path under $folder1
If (!(Test-Path($_.FullName.Replace($folder2, $folder1))))
{
$fileSuffix = $_.FullName.TrimStart($folder2)
$failedCount = $failedCount + 1
Write-Host "$fileSuffix is only in folder 2"
$fileSuffix | Out-File "$env:userprofile\desktop\folder2.txt" -Append
}
}