C program on how to use "dup" system call

C program on how to use "dup" system call 

neelkanth_surekha#cat dup.c 

#include "fcntl.h"

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/types.h>

int main()

{

    int i,j;

    char buf1[512],buf2[512];

    i = open("neel", O_RDONLY);

   /* by duplicating i, we can also use j to read  */

    j = dup(i);

    read(i, buf1, sizeof(buf1));

    lseek(i, 0,SEEK_SET);

    read(j, buf2, sizeof(buf2));

    printf("buf 1:%s buf 2: %s", buf1, buf2);

    close(i);

    read(j, buf2, sizeof(buf2));

    printf("buf 2: %s", buf2);

    return 0;

}

Output

neelkanth_surekha#./a.out 

buf 1:dfasdfsadfsadfsadfasf

 buf 2: dfasdfsadfsadfsadfasf

buf 2: dfasdfsadfsadfsadfasf