/*
In this example, the child process executes the command
"head -n 15". Its input is redirected from this file
(input-redirection.c)! The father process waits for the
child to finish, before continuing execution. This is
an example of how the "<" operator should work.

Compilation: gcc input-redirection.c -o input-redirection -Wall
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>

int main()
{
	int fd;
	char *argv[4];
	pid_t pid = fork();

	if (pid<0) {
		perror("fork() failed!");
		return -1;
	}
	if (pid==0) {
		fd = open("input-redirection.c",O_RDONLY);
		close(0);
		dup(fd);
		close(fd);
		argv[0] = (char*) malloc(5*sizeof(char));
		argv[1] = (char*) malloc(3*sizeof(char));
		argv[2] = (char*) malloc(3*sizeof(char));
		strcpy(argv[0],"head");
		strcpy(argv[1],"-n");
		strcpy(argv[2],"15");
		argv[3] = NULL;
		printf("OK\n");
		execvp(argv[0],argv);
	}

	waitpid(pid,NULL,0);
	printf("Father exitting...\n");
	return 0;
}