code: function exec(cmd) {
          return new Promise(
              function (resolve, reject) {
                  child_process.exec(cmd, function (error, stdout, stderr) {
                      if (error) {
                          reject(stderr.trim());
                      } else {
                          resolve(stdout.trim());
                      }
                  });
              }
          );
      }
docs: Helper function to run shell commands.