单项选择题 An operator notices that a job on the system is causing poor performance. The job is a root process and the administrator has concluded it is not important and can be stopped. Shortly after stopping the process, it starts again. Which of the following commands will list repeating scheduled tasks?（）

单项选择题 Which command enables a user to exit the vi editor, overwriting the existing file without prompting for confirmation?（）

单项选择题 User2 is complaining that he is unable to list the contents of a directory. What is the most likely cause?（）