#include <fcntl.h>  // open, close, O_RDONLY, ...
#include <stdio.h>  // perror
#include <unistd.h> // read, write

int main(int argc, char* argv[]) {
	int f1 = open(argv[1], O_RDONLY);
	if (f1 < 0) {
		perror("open");
		return 1;
	}

	int f2 = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0755);
	if (f2 < 0) {
		perror("open");
		return 2;
	}

	char buf;
	while(read(f1, &buf, 1)) {
		write(f2, &buf, 1);
	}

	close(f1);
	close(f2);
}