设计并实现Unix的“time”命令。“mytime”命令通过命令行参数接受要运行的程序，创建一个独立的进程来运行该程序，并记录程序运行的时间。

在Linux下实现:

• 　　使用fork()/execv()来创建进程运行程序

• 　　使用wait()等待新创建的进程结束

• 　　调用gettimeofday()来获取时间

-Design and implementation of the Unix " time"　command. " Mytime"　command via the command line parameter accepts the program to run, create a separate process to run the program, and recording program to run. Under Linux: •　Use a fork ()/execv () to create a process to run the program •　Use wait () to wait for the end of the newly created process •　call gettimeofday () to get the time