title: s3cmd Amazon s3 update metadata only
body: <p>I have a few GB of files on S3, and I need to mass update the metadata for all of them. I know that s3cmd can update the metadata when you transfer a file:</p>
  
  <p><code>
  s3cmd -m text/html --add-header='Content-Encoding: gzip' put [files] s3://...
  </code></p>
  
  <p>However I don't want to retransfer the files to S3. Can s3cmd update the metadata of a key <strong>only</strong> without transferring the file?</p>