1 /* 2  * stdinredir2.c 3  * shows two more methods for redirecting standard input 4  * use #define to set one or the other 5  */ 6 #include <stdio.h> 7 #include <fcntl.h> 8 /*#define CLOSE_DUP  /*open, close, dup, close */ 9 /*#define USE_DUP2   /*opne, dup2, close */10 int main(void) {11   int fd, newfd;12   char line[100];13   //read and print lines14   fgets(line, 100, stdin);15   printf("line: %s", line);16   17   fd=open("/home/wiz/wizcode/psh1.c", O_RDONLY);  /* open the disk file */18 19   #ifdef CLOSE_DUP20      close(0);21      newfd=dup(fd);              /*copy open fd to 0*/22   #else23      newfd=dup2(fd,0);           /*close 0, dup fd to 0*/24   #endif25   if(newfd!=0){26     fprintf(stderr, "Could not duplicate fd to 0\n");27     exit(1);28   }29   close(fd);30   fgets(line, 100, stdin); printf("%s", line);31   fgets(line, 100, stdin); printf("%s", line);32   fgets(line, 100, stdin); printf("%s", line);33   return 0;34 }