Renaming multiple file extensions based on a condition

Question

Hi I would like to rename a bunch of .bin files into .oma based on one condition: the first 4 bytes of the .bin files are supposed to include the string 'RIFF'. If it includes something else, then do not rename it.

I'm currently using Windows 7 Pro. Is there such automation software already built in that I can use?

I also need this automation to change a bunch of mp3 titles later on...

Answer 1

You can achieve this with the following script for the built-in Windows Powershell:

$files = get-childitem | where {$_.extension -eq '.bin'}

foreach ($f in $files)
{
    try
    {
        $reader = $f.Open([System.IO.FileMode]::Open)
        $bytes = new-object byte[] 4
        $numRead = $reader.Read($bytes, 0, $bytes.Count)
    }
    finally
    {
        if ($reader)
        {
            $reader.Dispose()
        }

        if ($numRead -eq 4)
        {
            $encoding = new-object "System.Text.ASCIIEncoding"
            if ($encoding.GetString($bytes) -eq "RIFF")
            {
                $newname = $f.Name.Replace(".bin", ".oma")
                rename-item $f -newname $newname
            }
        }
    }
}

Answer 2

I do not know "out of the box" solution.

Maybe write simple script on python or perl or whatever you like is simplest way.

Answer 3

Alright, someone had to post a bash solution.

find . -name '*.bin' -exec head -q -c 4 {} \; -exec printf ' %s' {} \; -exec printf '\n' \;  | grep RIFF | cut -d' ' -f2- | tr "\n" "\0" | xargs -0 rename -v 's/\.bin/\.oma/'

updates:

1. Support for filenames with spaces
2. Realized that the 'rev' trick was unnecessary if the execs were re-ordered, removed.