/*
In this example, the child process executes the command
"ls -l" and redirects the ls output to file
"example-output.txt". The father process waits for the
child to finish, before continuing execution. This is
an example of how the ">" operator should work.

Compilation: gcc output-redirection.c -o output-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[5];
	pid_t pid = fork();

	if (pid<0) {
		perror("fork() failed!");
		return -1;
	}

	if (pid==0) {
		fd = open("example-output.txt",
			O_CREAT|O_TRUNC|O_WRONLY, S_IRUSR|S_IWUSR);
		close(1);
		dup(fd);
		close(fd);
		argv[0] = (char*) malloc(5*sizeof(char));
		argv[1] = (char*) malloc(5*sizeof(char));
		strcpy(argv[0],"ls");
		strcpy(argv[1],"-l");
		argv[2] = NULL;
		execvp(argv[0],argv);
	}

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