#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

/* to test how dup() works. Specifically, want to learn how the pipe of the */
/* form cmd1 > out works */

int main(void)
{
    int fid;
    int exam;

    printf("hello before we are in\n");  /* this message actually goes to */
					 /* the screen */
    fid = open("pipe.test", O_WRONLY | O_CREAT );
    close(1);                            /* close the stdout */
    dup(fid);                            /* dup() uses fd[1] (stdout) */
    					 /* because the close(1) call was */
					 /* right before it. At this point, */
					 /* '1' becomes the lowest un-used */
					 /* file id number. Thus, it (1) */
					 /* will be used to 'dup' fid. This */
					 /* is exactly what we want Now all */
					 /* the output to stdout will be */
					 /* redirected to the file that */
					 /* 'fid' was associated with. */
    close(fid);
    printf("hello now we are in\n");     /* this message actually is printed */
					 /* to the file 'pipe.test' */
}