Find specific files by date modified and copy to the relevant folder - powershell

Question

I'm looking for a PowerShell script which can find the files (N30008xx.txt, N30005xx.txt) from the source directory and copy them to the destination directory by creating a folder with the same name of the file's modification date.
I'm able to run the below script which creates the folder by files modified date.
$p = "Filesourcepath"
Get-ChildItem -Path $p |
Where-Object { ! ($_.PSIsContainer) } |
ForEach-Object {
$newDir = Join-Path $p ($_.LastWriteTime).ToString("yyyy-MM-dd")
New-Item -Path $newDir -ItemType Directory -ErrorAction SilentlyContinue
$_ | Move-Item -Destination $newDir
}

Answer 1

Your code should work in principle.
(As of this writing, there's confusion over copying vs. moving, and the aspect of matching only select files is missing.)
Below is a streamlined version of your code, which however, does not explain your symptom - you need to provide more information for us to diagnose your problem.
The streamlined code below:
takes advantage of the PSv3+ -File Get-ChildItem parameter to limit matching to files (as opposed to directories) - this saves the need for Where-Object { ! $_.PSIsContainer }.
uses -LiteralPath to pass the literal $dir path; while -Path (which is also the positional default) often works fine too, it's important to note that it interprets is argument as a wildcard expression, which can have unexpected results).
uses -Filter to provide the file mask (wildcard expression); this is generally preferable to using the -Path parameter, because it filters at the source (Windows API call) and is therefore faster, which can make a noticeable difference when processing large directories.
Caveat: the wildcard language supported in the -Filter argument is more limited than PowerShell's and also burdened with legacy quirks; in short: sticking with * and ? should be fine; for the full story, see this well-researched answer.
uses -Force instead of -ErrorAction SilentlyContinue in order to either create a directory or use a preexisting one.
Note that New-Item -ItemType Directory -Force returns a [System.IO.DirectoryInfo] instance in both scenarios (either the newly created directory or the preexisting one), which the code takes advantage of.
# Create sample dir. with 2 sample files in it.
$tmpDir = New-Item -Force -Type Directory tmpDir
New-Item -Type File -Force -Path ('N30008xx.txt', 'N30005xx.txt' -replace '^', "$($tmpDir.FullName)/")
$dir = $tmpDir
$fileMask = 'N*.txt'
Get-ChildItem -File -LiteralPath $dir -Filter $fileMask | ForEach-Object {
$newDir = Join-Path $dir $_.LastWriteTime.ToString("yyyy-MM-dd")
$_ | Move-Item -Destination (New-Item -ItemType Directory -Force $newDir)
}
Caveat re generalization of this code:
You're creating the target subdirectories inside the source directory.
If you were to use Get-ChildItem -Recurse to process the source directory recursively, you'd end up processing matching files twice: first when moving them, and then again when finding them in their moved-to location.
(In this particular case this would only cause an inefficiency, however, because processing the already-moved files attempts to move them into the directory where they already are, which is a quiet no-op.)

Answer 2

Here is a modified version of your PowerShell that should work.
Note: Your destination directory cannot be located under the source directory otherwise you will have a forever recursive move.
$p = pwd
$dst = "c:/tmp/testdir"
Get-ChildItem -Path $p | Where-Object {
$_.PSIsContainer -eq $false
} | ForEach-Object {
$newdir = Join-Path -Path $dst -ChildPath ($_.LastWriteTime).ToString("yyyy-MM-dd")
if (!(Test-Path -Path $newdir)) {
Write-Host "Create directory $newdir"
New-Item -Path $newdir -ItemType Directory
}
Write-Host "Copy file $_"
Move-Item -Path $_ -Destination $newdir
}