code: function put(argv, callback) {
    if (!argv[2]) {
      console.error("url is required");
      console.error("Usage : put <url> <data>");
      process.exit(-1);
    }
    if (!argv[3]) {
      console.error("data is required");
      console.error("Usage : put <url> <data>");
      process.exit(-1);
    }
    util.put(argv[2], argv[3], function(err, val, uri) {
      if (!err) {
        console.log('PUT to : ' + argv[2]);
      }
    });
  }
docs: put gets list of files for a given container
  
  @param {String} argv[2] url
  @param {String} argv[3] data
  @callback {bin~cb} callback