Powershell moving files but backup the files before replacing - powershell

Question

I have three directories:
1. RFC
2. Source
3. Backup
RFC contains files and folders(that contain files) that I need to replace in the source folder but before I replace/move files I need to backup the files I'm replacing from source to the backup folder.
I have wrote the following code, which compares RFC and Source and copies the files to backup, but it doesn't copy sub directories. I want it to move files within the sub directories as well with the same folder structure as Source. And once the copy of the files is done. I want to move files from RFC to Source.
Please any help would be highly appreciated.
$source = "C:\Scripts\Source\"
$backup = "C:\Scripts\Destination\"
$rfc_dir = "C:\Scripts\RFC000001234\"
$folder1Files= dir $source
$folder2Files= dir $rfc_dir
compare-object $folder1Files $folder2Files -property name -includeEqual -excludeDifferent | ForEach-object {
copy-item "$source\$($_.name)" -Destination "$backup" -Force -recurse
}

Answer 1

UPDATE
TL;DR -- the script
$RFC_Folder = 'c:\scripts\rfc'
$SOURCE_Folder = 'c:\scripts\source'
$BACKUP_Folder = 'c:\scripts\backup'
$rfc = get-ChildItem -File -Recurse -Path $RFC_Folder
$source = get-ChildItem -File -Recurse -Path $SOURCE_Folder
compare-Object -DifferenceObject $rfc -ReferenceObject $source -ExcludeDifferent -IncludeEqual -Property Name -PassThru | foreach-Object {
# copy SOURCE to BACKUP
$backup_dest = $_.DirectoryName -replace [regex]::Escape($SOURCE_Folder),$BACKUP_Folder
# create directory, including intermediate paths, if necessary
if ((test-Path -Path $backup_dest) -eq $false) { new-Item -ItemType Directory -Path $backup_dest | out-Null}
copy-Item -Force -Path $_.FullName -Destination $backup_dest
#copy RFC to SOURCE
$rfc_path = $_.fullname -replace [regex]::Escape($SOURCE_Folder),$RFC_Folder
copy-Item -Force -Path $rfc_path -Destination $_.FullName
}
The explanation:
Given the OPs comment below on ROBOCOPY not being preferable I've updated the answer.
Your posted script is basically on the right track, however instead of using just $backup you have to get a little fancy with the -Destination parameter. You don't want the -Destination to be the static path c:\scripts\backup you want it to update based on where the source file actually was. For example if the file was in c:\scripts\source\subdir1\subdir2, you'd want -Destination to be c:\scripts\backup\subdir1\subdir2.
$_.FullName will be the path to the $SOURCE_Folder as it was used as the -ReferenceObject. It's getting manipulated stringwise to create the desired RFC and Backup paths. The [regex]::Escape static method is being used because the -replace operator does a regular expression operation on the strings, and several characters in paths need to be escaped (the slash, mainly). All it's doing is turning c:\scripts\source into a regular expression escaped version: c:\\scripts\\source
The if construct is used because copy-Item doesn't create intermediate directories, but new-Item does.
Depending on your specifics this might work as is, but you may have to alter it. For example if somehow a directory can end up in RFC that wasn't in SOURCE, this wouldn't catch that. It also won't catch any empty directories that are in SOURCE and RFC, if that's important.
It may be that PowerShell isn't the best tool for this job, depending on some other factors. As I understand it you have Source, RFC and Backup folders. The RFC folder will contain changes that need to be committed to Source, but before you do that you want to backup Source to Backup. If the folder structures are all similar between them, then perhaps the command line tool ROBOCOPY could do what you need?
If some of my assumptions are correct you'd first mirror the Source folder with the Backup folder. This would contain the pre-changed files. Then you would mirror the RFC folder to Source, this would commit any changed files/folders from RFC to the Source folder. An example (this is a batch file):
REM Mirror the Source folder to Backup
ROBOCOPY C:\Scripts\Source C:\Scripts\Backup /MIR
REM Mirror the RFC folder to Source
ROBOCOPY C:\Scripts\RFC C:\Scripts\Source /MIR
At the end of all this your Source folder would be an exact replica of whatever the RFC folder looked like. If RFC isn't a full copy of Source, but rather a partial copy, then you wouldn't want to use the mirror switch, /MIR, as it would destroy anything in Source that wasn't in RFC.
Browse around ROBOCOPY /? for some of its other switches, it's got a few interesting ones for logging if you want to build in some auditing capability. Also, make extra sure to test this in a test environment. Misuse of ROBOCOPY with a /MIR switch might make you a very sad camper.