A quick first pass at turning request.js options object into a curl command. Much work needed here for escaping and edge cases.

requestjs2curl.js

function request2Curl(options) {
  var tokens = ['curl', '-v', '-k', '-ssl3'];

  if ( _.has(options, 'auth') ) {
    if ( _.has(options.auth, 'user') ) {
      tokens.push('--user', "'" + options.auth.user + ":" + options.auth.pass + "'");
    }
  }

  var isPost = _.has(options, 'method') && options.method.toLowerCase() == 'post';
 
  if ( isPost ) {
    tokens.push('-X', 'POST');
  }

  if ( _.has(options, 'headers') ) {
    _.each(options.headers, function(value,key) {
      tokens.push('-H', "'" + key + ':' + value + "'");
    });
  }

  if ( _.has(options, 'json') ) {
    tokens.push('-H', "'Content-Type:application/json'");
    if ( options.json !== true ) {
      tokens.push('-d', "'" + JSON.stringify(options.json) + "'");
    }
  }

  if ( _.has(options, 'qs') ) {
    var parsedUrl = url.parse(options.url);
    if ( ! isPost ) {
      if ( parsedUrl.query == null ) {
        parsedUrl.query = options.qs;
      } else {
        parsedUrl.query = parsedUrl.query + '&' + querystring.encode(options.qs);
      }
      options.url = url.format(parsedUrl);
    }
  }

  tokens.push("'" + options.url + "'");
  return tokens.join(" ");
}