code: func (t *T) Exec(cmd ...string) (err error) {
  	toRun := strings.Join(cmd, " ")
  	input, err := shellquote.Split(toRun)
  	if err != nil {
  		return
  	}
  	err = execCmd(input)
  
  	return
  }
docs: // Exec runs the system command. If multiple arguments are given, they're concatenated to one command.
  //
  // Example:
  //   t.Exec("ls -ltr")
  //   t.Exec("ls", FILE1, FILE2)