How to batch rename files including a number and the modified date?

Edit: I should have gone for Date Taken instead, as Date Modified is sometimes off by one hour for the pictures we're working with.

I am trying to write something that will rename files to the following format:

24024 25-12-2014 20.18.JPG
24025 26-12-2014 18.01.JPG
24026 26-12-2014 18.01.JPG
24027 30-12-2014 17.05.JPG
24028 31-12-2014 15.09.JPG
24029 31-12-2014 15.19.JPG

I need this for organising my mother's pictures in the way my father designed. I looked specifically for ways to do it with a cmd batch file first, but it seemed too complicated. I am now trying to use the PowerShell.

I have tried this, which works:

Get-ChildItem *.JPG | Rename-Item -newname {$_.LastWriteTime.toString("dd-MM-yyyy HH.mm") + ".JPG"}

But I haven't managed to include a variable counting with that. This does not compile:

$a = 10; Get-ChildItem *.JPG | {Rename-Item -newname {$_.LastWriteTime.toString("dd-MM-yyyy HH.mm") + ".JPG"}; $a++}

Nor does this, which I found in another question.

Foreach ($Item in Get-ChildItem *.JPG) {Rename-Item -newname {$_.LastWriteTime.toString("dd-MM-yyyy HH.mm") + ".JPG"}}

Solution

You could do something like this:

$Path = 'D:\'  # the folder where the jpg files are
$Count = 10    # the starting number. gets increased for each file
Get-ChildItem -Path $Path -Filter '*.JPG' -File | ForEach-Object {
    $_ | Rename-Item -NewName ('{0:00000} {1}.JPG' -f $Count++, ($_.LastWriteTime.toString("dd-MM-yyyy HH.mm")))
}

EDIT 1

To name them in chronological order, just add a Sort-Object to the script, like this:

$Path = 'D:\'  # the folder where the jpg files are
$Count = 10    # the starting number. gets increased for each file
Get-ChildItem -Path $Path -Filter '*.JPG' -File | Sort-Object LastWriteTime | ForEach-Object {
    $_ | Rename-Item -NewName ('{0:00000} {1}.JPG' -f $Count++, ($_.LastWriteTime.toString("dd-MM-yyyy HH.mm")))
}

EDIT 2

As per your last comment, to get the date from the Exif data in the image, you need a function to get the DateTimeOriginal from the file if possible.

You can do that with the code below:

function Get-ExifDate {
    # returns the 'DateTimeOriginal' property from the Exif metadata in an image file if possible
    [CmdletBinding(DefaultParameterSetName = 'ByName')]
    Param (
        [Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, Position = 0, ParameterSetName = 'ByName')]
        [Alias('FullName', 'FileName')]
        [ValidateScript({ Test-Path -Path $_ -PathType Leaf})]
        [string]$Path,

        [Parameter(Mandatory = $true, ValueFromPipeline = $true, Position = 0, ParameterSetName = 'ByObject')]
        [System.IO.FileInfo]$FileObject
    )

    Begin {
        Add-Type -AssemblyName 'System.Drawing'
    }
    Process {
        # the function received a path, not a file object
        if ($PSCmdlet.ParameterSetName -eq 'ByName') {
            $FileObject = Get-Item -Path $Path -Force -ErrorAction SilentlyContinue
        }
        # Parameters for FileStream: Open/Read/SequentialScan
        $streamArgs = @(
            $FileObject.FullName
            [System.IO.FileMode]::Open
            [System.IO.FileAccess]::Read
            [System.IO.FileShare]::Read
            1024,     # Buffer size
            [System.IO.FileOptions]::SequentialScan
        )
        try {
            $stream = New-Object System.IO.FileStream -ArgumentList $streamArgs
            $metaData = [System.Drawing.Imaging.Metafile]::FromStream($stream)

            # get the 'DateTimeOriginal' property (ID = 36867) from the metadata
            # Tag Dec  TagId Hex  TagName           Writable  Group    Notes
            # -------  ---------  -------           --------  -----    -----
            # 36867    0x9003     DateTimeOriginal  string    ExifIFD  (date/time when original image was taken)
            # see: https://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/EXIF.html

            # get the date taken as an array of bytes
            $exifDateBytes = $metaData.GetPropertyItem(36867).Value
            # transform to string, but beware that this string is Null terminated, so cut off the trailing 0 character
            $exifDateString = [System.Text.Encoding]::ASCII.GetString($exifDateBytes).TrimEnd("`0")
            # return the parsed date
            return [datetime]::ParseExact($exifDateString, "yyyy:MM:dd HH:mm:ss", $null) 
        }
        catch{
            Write-Warning -Message "Could not read Exif data from '$($FileObject.FullName)'"
        }
        finally {
            If ($metaData) {$metaData.Dispose()}
            If ($stream)   {$stream.Close()}
        }
    }
}

Using that function, your code would look then like this:

$Path = 'D:\'  # the folder where the jpg files are
$Count = 10    # the starting number. gets increased for each file

# start a loop to gather the files and reset their LastWriteTime property to the one read from the Exif data.
# pipe the result to the Sort-Object cmdlet and enter another ForEach-Object loop to perform the rename.
Get-ChildItem -Path $Path -Filter '*.JPG' -File | ForEach-Object {
    $date = $_ | Get-ExifDate
    if ($date) { 
        $_.LastWriteTime = $date
    }
    $_
} | Sort-Object LastWriteTime | ForEach-Object {
    $newName = '{0:00000} {1}.JPG' -f $Count++, ($_.LastWriteTime.toString("dd-MM-yyyy HH.mm"))
    # output some info to the console
    Write-Host "Renaming file '$($_.Name)' to '$newName'"
    $_ | Rename-Item -NewName $newName
}

This uses string formatting -f. You give it a template string with numbered placeholders between curly braces.

The first one {0:00000} is a way of formatting a number with preceeding zero characters up to a length of 5 characters in this case.

The second one {1} gets replaced by the formatted date string.

The $Count variable gets increased on each iteration using the ++ syntax.