Renaming a folder, and merging with exisiting folder if it exists in Powershell

Question

Trying to do some directory cleanups, and transition from an old methodology to a new one. Currently we've been doing it manually, case-by-case, but I decided to look into automating the process.

This worked in theory until we started extracting more CSV data, and ran into new issues.

What I cannot find an answer for anywhere is "renaming a folder, and if the name exists then merge the two" exactly like you would see in Windows Explorer:

I know this is dangerous - but its the only way I can think of it.

I looked into Copy-Item but since the folders range from a few MB all the way to >20GB (and on average at the larger side). It's too slow to copy, move child items, then delete - plus with about 8000 folders to create and move I don't think there's enough buffer storage.

Is it possible to merge the folders, and sub folders into the newly created one?

This is what I have so far:

# set the working directory
Set-Location "B:\"

# import the CSV file for folder creation
$folders = Import-Csv -Delimiter "," -Header @("ID","caseName","caseNumber") -Path .\export.csv

# begin the loop
ForEach( $folder in $folders ) {

   # create the variables
   $columnID = $folder.ID
   $columnCase = "{0} {1}" -f $folder.caseName, $folder.caseNumber
   $columnNewCase = "{1}, {0}" -f $folder.caseName, $folder.caseNumber

   # use later to create root folders
   $yearAllocation = "20{0}" -f $folder.caseNumber.Substring(0,2)


   #
   # // MARK: begin main folder creation
   #

   # "SMITH 12345678" and "12345678, SMITH" do NOT exist
   if( (-not ( Test-Path "$columnCase" )) -and (-not ( Test-Path "$columnNewCase" )) ) {
       # create the "12345678, SMITH"
       New-Item "$columnNewCase" -ItemType Directory
   }

   # "SMITH 12345678" EXISTS but "12345678, SMITH" does NOT exist
   if( ( Test-Path "$columnCase" ) -and (-not ( Test-Path "$columnNewCase" )) ) {
       # rename "SMITH 12345678" -> "12345678, SMITH"
       Rename-Item "$columnCase" -NewName $columnNewCase -Force
   }

   # "SMITH 12345678" does NOT exist but "12345678, SMITH" EXISTS
#   if( (-not ( Test-Path "$columnCase" )) -and ( Test-Path "$columnNewCase" ) ) {
#      # do nothing
#   }

   # "SMITH 12345678" and "12346578, SMITH" both EXIST
   if( ( Test-Path "$columnCase" ) -and ( Test-Path "$columnNewCase" ) ) {
       # merge "SMITH 12345678" -> "12345678, SMITH"
   }


   #
   # // MARK: begin ID folder moves
   #

   # if "98765" folder exists
   if( Test-Path "$columnID" ) {
       # move "98765" into "12345678, SMITH"
       Move-Item "$columnID" -Destination "$columnNewCase"
   }
} 

In the end I'd hope that we could get something that looks like this currently:

B:\
- 12345
- 23445
- 63574
- 73363
- SMITH 12345678
- JONES 58478945

into:

B:\
- 12345678, SMITH
--- 12345
--- 23445
- 58478945, JONES
--- 63574
--- 73363

and if someone accidentally created a new manual folder:

B:\
- 12345678, SMITH
--- 12345
--- 23445
- 58478945, JONES
--- 63574
--- 73363
- SMITH 12345678
--- 66684

then re-running the script would simply:

B:\
- 12345678, SMITH
--- 12345
--- 23445
--- 66684
- 58478945, JONES
--- 63574
--- 73363

Answer 1

Turns out there isn't a way to merge folders in Powershell.

I ended up solving the problem by scanning all the subfolders in the original folder and moving them into the new destination.

As a precaution then move the original folder into another destination so we could do a file size property check if anything was missed.

# set the working directory
Set-Location "C:\"

# import the CSV file for folder creation
# create the headers for the file since CSVs dont have them
$csvRows = Import-Csv -Delimiter "," -Header @("ID","name","number") -Path .\file.csv

# begin the loop
    ForEach( $csvRow in $csvRows ) {

    # create the variables
    $columnID = $csvRow.ID
    $columnNameNumber = "{0} {1}"  -f $csvRow.name, $csvRow.number
    $columnNumberName = "{1}, {0}" -f $csvRow.name, $csvRow.number


    #
    # // MARK: begin main folder creation
    #

    # "SMITH 12345678" and "13246578, SMITH" do NOT exist
    if( (-not ( Test-Path "$columnNameNumber" )) -and (-not ( Test-Path "$columnNumberName" )) ) {
        # create the "12345678, SMITH"
        New-Item "$columnNumberName" -ItemType Directory
    }

    # "SMITH 12345678" EXISTS but "13246578, SMITH" does NOT exist
    if( ( Test-Path "$columnNameNumber" ) -and (-not ( Test-Path "$columnNumberName" )) ) {
        # rename "SMITH 12345678" -> "12345678, SMITH"
        Rename-Item "$columnNameNumber" -NewName $columnNumberName -Force
    }

    # "SMITH 12345678" does NOT exist but "13246578, SMITH" EXISTS
    if( (-not ( Test-Path "$columnNameNumber" )) -and ( Test-Path "$columnNumberName" ) ) {
        # do nothing
    }

    # "SMITH 12345678" and "13246578, SMITH" both EXIST
    if( ( Test-Path "$columnNameNumber" ) -and ( Test-Path "$columnNumberName" ) ) {
        # find all the items in $columnNameNumber
        $subDirectory = Get-ChildItem $columnNameNumber -Name

        # loop through and move to $columnNameNumberNew
        ForEach( $childItem in $subDirectory ) {
            Move-Item "$columnNameNumber\$childItem" -Destination "$columnNumberName"
        }

        # rename to know its done
        if( ( Test-Path .\destination ) ) {
            Move-Item "$columnNameNumber" -Destination .\destination
        }
    }


    #
    # // MARK: begin ID folder moves
    #

    # if "98765" folder exists
    if( Test-Path "$columnID" ) {
        # move "98765" into "12345678, SMITH"
        Move-Item "$columnID" -Destination "$columnNumberName"
    }
}

Hope this helps someone in the future!