In uncovered Dutch oven cook linguini in boiling water, cooking oil and salt until tender but firm, about 11 to 13 minutes. Drain.
Toss linguini with butter.
Meanwhile, in olive oil, saute onion and garlic until soft. Add clam juice, second amount of salt, pepper and parsley. Simmer until volume of juice is reduced by half. Add clams and wine, adding more wine to taste. Heat through. Place linguini on warm platter. Pour clam sauce over top.
Sprinkle with Parmesan cheese.