Myshell(linux).txt

   #include<stdio.h>
   #include<stdlib.h>
   #include<unistd.h>
   #include<sys/types.h>
   #include<sys/wait.h>
   #include <sys/stat.h>
   #include <fcntl.h>
   #include<string.h>
   int main()
    {
      while(1)
      {
        printf("[myshell@myhostname test]# ");
        fflush(stdout);
        char buf[1024];
        ssize_t s= read(0,buf,sizeof(buf)-1);//[*]
        if(s>0)
        {
            buf[s-1]=0;
        }
  
        char* argv[32];
        char* start = buf;
        argv[0]=buf;
  
        int i = 1;
        while(*start)
        {
            if(*start==' ')
            {
                *start=0;
                 start++;
                 argv[i++]=start;
            }
            else 
              start++;
        }
        argv[i]=NULL;
       if(strcmp(argv[i-2],">") == 0)//  ">"  exp: ls>Makefile
        {
           argv[i-2] = NULL;
           pid_t id = fork();
           if(id == 0)
                {//child
                    close(1);
                    open(argv[i-2],O_WRONLY|O_CREAT,0666);
                   int ret =  execvp(argv[0],argv);
                   if(ret == 0)
                       perror("execerror!");
                       exit(1);
                }
        }
        pid_t id = fork();
        if(id==0)
           {//child
             int ret = execvp(argv[0],argv);
               if(ret==0)
                   perror("execerror!");
                   exit(1);
            }
       else
       {//father
           wait(NULL);
        }
  
      }
      return 0;
    }