# includestdio.h>   
  #includestdlib.h> 
  #includeunistd.h>  
  #includefcntl.h>  
  #includesys/types.h>
  #includesys/stat.h>                                                  
  #includestring.h>  
  int main()     
   {         
    pid_t id=fork(); 
  if(id==0)      
   {        
   printf("child is running\n");
   sleep(1);    
  char* env[]={"MYENV=/A/B/C/D/AAAA",NULL};
  char* argv[]={"ls","-l","-n","-i",NULL};
 // execl("/bin/ls","ls","-l","-n","-i",NULL);
  // execlp("ls","ls","-l","-n","-i",NULL);
 //  execv("/bin/ls",argv); 
  // execvp("ls",argv);
            
             
   // execle("./myenv","myenv",NULL,env);
      execve("./myenv",argv,env);    
      printf("child id done\n");  //exec成功的話不執行此語句
      exit(1);   
    }               
    else                                                        
    {         
       pid_t ret=waitpid(id, NULL,0);
      if(ret>0)  
       {      
        printf("father wait success\n"); }
         else{  
          printf("child quit not normal\n");
            
       }   }   return 0;                                              }