Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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...

share|improve this question
you mean bin file of size 4 bytes should be re-named with a pre-fix RIFF – subanki Sep 10 '10 at 9:42
No... is my description too vague? :/ – FlavorOfLife Sep 10 '10 at 10:13
up vote 3 down vote accepted

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)
        $reader = $f.Open([System.IO.FileMode]::Open)
        $bytes = new-object byte[] 4
        $numRead = $reader.Read($bytes, 0, $bytes.Count)
        if ($reader)

        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
share|improve this answer
Kudos Steve, how do I specify the location of my files? I've never used PowerShell before. – FlavorOfLife Sep 11 '10 at 11:50
Steve! I'm nearly there! Please reply so I can tick it as the answer! :) – FlavorOfLife Sep 13 '10 at 23:18
As it stands, the script will just run on files in the directory PowerShell is in. To run on a specific directory, the quickest way to alter the script is to call set-location before any of the above - e.g. "set-location C:\path\to\the\files\" (without the quotes) as first line. – Steve Beedie Sep 14 '10 at 15:23
Cheers Steve, I had a little trouble with execution policies, but after that it all works! (first time PowerShell user) – FlavorOfLife Sep 15 '10 at 5:48

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

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

share|improve this answer
Thanks, I've yet gathered the courage and time to learn a programming language though :) – FlavorOfLife Sep 11 '10 at 11:56

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/'


  1. Support for filenames with spaces
  2. Realized that the 'rev' trick was unnecessary if the execs were re-ordered, removed.
share|improve this answer
Sorry I'm not familiar with bash... I've heard of it though. Do I just run it through cmd? Where do I specify my folder directory? – FlavorOfLife Sep 11 '10 at 11:48

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.