Powershell：Get-ChildItem，获取同名文件的最新文件

Question

I got a script to get files from a folder that I then put in a HTML-Table and mail. In the folder you have files like HR May 2020 , HR April 2020 , RR May 2021 etc.

Below is the code itself as a sample, this looks for other files but they come every month as well. In total I will filter 8 files.

Get-ChildItem -Path D:\Temp\Test | 
    Where-Object { $_.Name -match '^RR_Prognos.*|^AllokeringBogNycklar.*' } | 
    Sort-Object -Property LastWriteTime | 
    Select-Object LastWriteTime,FullName

Now I am only interested in seeing the latest file of each, so using last or -days, month, hours or similar wont work.

I tried to find a better solution googling it but could not come up with anything that solved the problem.

So I just need to add to the code it it picks the lastest of each file i filter on, the filter is so it does not care about the month in the name.

Edit: Lets say I would use:

Get-ChildItem -Path c:\tm1 | Where-Object { $_.Name -match '^RR_Prognos.*|^AllokeringBogNycklar.*|^Aktivversion.*|^AllokeringNycklar.*|^HR_prognos.*|^KostnaderDK.*|KostnaderProdukt_prognos.*|^Parametrar_prognos.*|ProduktNyckel_prognos apr.*' } | Sort-Object -Property LastWriteTime -Descending | Select-First 8 | Select-Object LastWriteTime,FullName

Then if one file does not come with the batch, it would show the 2nd last one of that as well. Is there a easier way to block that from happening?

Answer 1

Ok, now that you've provided the whole list that you filter against I can write up a real answer. Here we'll group by file name, then sort each group and grab the last one from each group:

Get-ChildItem -Path c:\tm1 | 
    Where-Object { $_.Name -match '^RR_Prognos.*|^AllokeringBogNycklar.*|^Aktivversion.*|^AllokeringNycklar.*|^HR_prognos.*|^KostnaderDK.*|KostnaderProdukt_prognos.*|^Parametrar_prognos.*|ProduktNyckel_prognos apr.*' } | 
    Group {$_.Name -replace '.*?(^RR_Prognos|^AllokeringBogNycklar|^Aktivversion|^AllokeringNycklar|^HR_prognos|^KostnaderDK|KostnaderProdukt_prognos|^Parametrar_prognos|ProduktNyckel_prognos apr).*','$1'} | 
    ForEach-Object {
        $_.Group |
            Sort-Object -Property LastWriteTime -Descending | 
            Select -First 1
    } | 
    Select-Object LastWriteTime,FullName

Answer 2

This might be what you are looking for. This iterates over each search string where you need the newest file.

$searchStrings = @('^pattern1*', '^pattern2*', '^pattern3*')
foreach($searchString in $searchStrings) {
        $items = Get-ChildItem -Path $folder |  Where-Object { $_.Name -match "$searchString" } | Sort-Object -Property LastWriteTime -Descending
        $newestItem = $items[0]
        Write-Host "newest item for '$searchString' is $newestItem"
}