#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>

int main (int ac, char *const *av)
{
	const char *fname;
	int fd;
	off_t offset;

	if (ac != 3)
		error (1, 0, "usage: offset fname");

	offset = strtoull (av[1], 0, 0);
	fname = av[2];

	fd = open (fname, O_CREAT | O_EXCL | O_WRONLY, 0600);
	if (fd < 0)
		error (1, errno, "open: %s", fname);

	if (lseek (fd, offset - 1, SEEK_SET) == (off_t)-1)
		error (1, errno, "lseek: %#llx", (unsigned long long) offset);

	if (write (fd, "", 1) < 0)
		error (1, errno, "write: %s", fname);

	if (close (fd) < 0)
		error (1, errno, "close: %s", fname);

	return 0;
}