Using powershell to copy new and updated files - powershell

Question

I am a complete novice when it comes to powershell, but I have been given a script that I need to improve so that we can move updated or new files from one server to another. I've managed to get to grips with the current script but am struggling to find the right cmdlets and paramters to achieve the desired behaviour.
The script I have is successful at detecting changed files and moving them to a location ready for transfer to another server, but it doesn't detect any new files.
Can anyone give me some guidance as to how I would be able to achieve both behaviours?
$CurrentLocation = "C:\current"
$PreviousLocation = "C:\prev"
$DeltaLocation = "C:\delta"
$source = #{}
#
# Get the Current Location file information
#
Get-ChildItem -recurse $CurrentLocation | Foreach-Object {
if ($_.PSIsContainer) { return }
$source.Add($_.FullName.Replace($CurrentLocation, ""), $_.LastWriteTime.ToString())
}
Write-Host "Content of Source"
$source
$changesDelta = #{}
$changesPrevious = #{}
#
# Get the Previous Directory contents and compare the dates against the Current Directory contents
#
Get-ChildItem -recurse $PreviousLocation | Foreach-Object {
if ($_.PSIsContainer) { return }
$File = $_.FullName.Replace($PreviousLocation, "")
if ($source.ContainsKey($File)) {
if ($source.Get_Item($File) -ne $_.LastWriteTime.ToString()) {
$changesDelta.Add($CurrentLocation+$File, $DeltaLocation+$File)
$changesPrevious.Add($CurrentLocation+$File, $PreviousLocation+$File)
}
}
}
Write-Host "Content of changesDelta:"
$changesDelta
Write-Host "Content of changesPrevious:"
$changesPrevious
#
# Copy the files into a temporary directory
#
foreach ($key in $changesDelta.Keys) {
New-Item -ItemType File -Path $changesDelta.Get_Item($key) -Force
Copy-Item $key $changesDelta.Get_Item($key) -Force
}
Write-Host $changesDelta.Count "Files copied to" $DeltaLocation
#
# Copy the files into the Previous Location to match the Current Location
#
foreach ($key in $changesPrevious.Keys) {
Copy-Item $key $changesDelta.Get_Item($key) -Force
}

Answer 1

Here's a simplified approach to your needs. One thing to note is that some of the constructs I've used require PSv3+. This does not copy directory structure, just the files. Additionally, it compares the basenames (ignoring extensions) which may or may not do what you want. It can be expanded to include extensions by using .Name instead of .BaseName
#requires -Version 3
$CurrentLocation = 'C:\current'
$PreviousLocation = 'C:\prev'
$DeltaLocation = 'C:\delta'
$Current = Get-ChildItem -LiteralPath $CurrentLocation -Recurse -File
$Previous = Get-ChildItem -LiteralPath $PreviousLocation -Recurse -File
ForEach ($File in $Current)
{
If ($File.BaseName -in $Previous.BaseName)
{
If ($File.LastWriteTime -gt ($Previous | Where-Object { $_.BaseName -eq $File.BaseName }).LastWriteTime)
{
Write-Output "File has been updated: $($File.FullName)"
Copy-Item -LiteralPath $File.FullName -Destination $DeltaLocation
}
}
Else
{
Write-Output "New file detected: $($File.FullName)"
Copy-Item -LiteralPath $File.FullName -Destination $DeltaLocation
}
}
Copy-Item -Path "$DeltaLocation\*" -Destination $PreviousLocation -Force