code: function runCommand(cmd) {
    return exec(cmd).catch(err =>
      Promise.reject(
        err.message && err.message.indexOf('not found') !== -1
          ? new Error(`${cmd.split(' ')[0]} must be installed to upload`)
          : err
      )
    )
  }
docs: Run shell command with error handling.
  @param  {String} cmd - Command to run
  @return {Promise} Resolves with stdout of running command
  @private