void
c_copy(char *c, char **argv) {
	c += 2;
	int start = atoi(c);
	for(; *c != '\0' && *c != ' '; c++);
	int end = atoi(c);
	Row *cpy_start = b_getline(buffer, start);
	if(cpy_start == NULL || b_getline(buffer, end) == NULL) {
		puts("invalid line.");
		return;
	}
	if (clipboard != NULL) {
		b_truncate(clipboard);
		free(clipboard);
	}
	clipboard = calloc(1, sizeof(Row));
	Row *dest = clipboard;
	for (int i = start; i <= end; i++) {
		memcpy(dest->text, cpy_start->text, ROW_SIZE);
		cpy_start = cpy_start->n;
		dest = b_insert(dest);
	}
}

void
c_paste(char *c, char **argv) {
	Row *line = b_getline(buffer, atoi(c + 2));
	if (line == NULL) {puts("invalid line."); return; }
	if (clipboard == NULL) {puts("empty clipboard"); return; }
	for (Row *cb = clipboard; cb->n != NULL; cb = cb->n) {
		line = b_insert(line);
		memcpy(line->text, cb->text, ROW_SIZE);
	}
}