Renaming/Copying file with complicated name requirements - powershell

Question

I have to create a script that searches for file, takes part of the folder name and move the file to a new location with that new name.
I am planning to use powershell for this but would be up willing to look for other options. This used for millions of files.
Example 1
sourcefolder\a\b\test_123456\example.txt -> \destinationfolder\example_123456.txt
Problem is I don't know how many folders deep the file is and the amount of folder name changes, I need everything after the last _
Example 2
sourcefolder\a\b\c\test_test_1234\example.txt -> \destinationfolder\example_1234.txt
I am researching how to script and will update question when I when I have some progress

Answer 1

FileInfo objects include many properties. One of these is the .Directory property which returns the directory (as DirectoryInfo object) that represents the parent folder the file is in. This Directory also has properties, like .Name.
You can use this like below:
$sourceFolder = 'D:\Test' # the root folder to search through
$destinationFolder = 'X:\Archive' # the destinationpath for the moved files
# make sure the destination folder exists
$null = New-Item -Path $destinationFolder -ItemType Directory -Force
# get a collection of FileInfo objects
# if you need more file extensions like both .txt and .log files, replace -Filter '*.txt' with -Include '*.txt', '*.log'
# this will be slower than using -Filter though..
$filesToMove = Get-ChildItem -Path $sourceFolder -File -Filter '*.txt' -Recurse | Where-Object {$_.Directory.Name -like '*_*'}
# using a foreach(..) is a bit faster than 'ForEach-Object'
foreach ($file in $filesToMove) {
# get the last part after '_' of the parent directory name
$suffix = ($file.Directory.Name -split '_')[-1]
# combine to create the new path and filename
$target = Join-Path -Path $destinationFolder -ChildPath ('{0}_{1}{2}' -f $file.BaseName, $suffix, $file.Extension)
$file | Move-Item -Destination $target -Force -WhatIf
}
Take off the WhatIf safety switch if you are satisfied what is displayed on screen about what would be moved is correct.
You don't even need the foreach loop because Move-Item can handle a scriptblock as parameter for the Destination like this:
$sourceFolder = 'D:\Test' # the root folder to search through
$destinationFolder = 'X:\Archive' # the destinationpath for the moved files
# make sure the destination folder exists
$null = New-Item -Path $destinationFolder -ItemType Directory -Force
# get a collection of FileInfo objects
# if you need more file extensions like both .txt and .log files, replace -Filter '*.txt' with -Include '*.txt', '*.log'
# this will be slower than using -Filter though..
$filesToMove = Get-ChildItem -Path $sourceFolder -File -Filter '*.log' -Recurse |
Where-Object {$_.Directory.Name -like '*_*'} |
Move-Item -Destination {
$suffix = ($_.Directory.Name -split '_')[-1]
Join-Path -Path $destinationFolder -ChildPath ('{0}_{1}{2}' -f $_.BaseName, $suffix, $_.Extension)
} -Force
Here, the $_ Automatic variable is used instead of a variable you define in a foreach loop.
P.S. If you only need files from subfolders with a name ending in _ followed by numbers only as opposed to names like sub_folder, change the Where-Object {...} clause in the code to
Where-Object {$_.Directory.Name -match '_\d+$'}