test.c

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

main()

{
  int fd[2];
  int n=0, i;

  pipe(fd);

  if (fork() == 0) {
    /* Child process */

    close(1); dup(fd[1]) ; /* Redirect the stdout of this process to the pipe.*/
    close(fd[0]);       /* This process will not read from the pipe in this example.  Hence we close fd[0].*/
    execlp("ls","ls","-l",(char *)NULL);
  } else {

    /* Parent process */
    close(0); dup(fd[0]) ; /* Redirect the stdin of this process to the pipe */
    close(fd[1]);/* In this example, this process will not write into the pipe. Hence we close fd[1].*/
    execlp("wc","wc","-c",(char *)NULL);

  }

}