Cook linguini according to package directions; drain and keep warm.
Meanwhile, in a large skillet, heat 2 tablespoons butter over medium-high heat; saute mushrooms and green pepper until tender. Stir in salt and pepper; remove from pan.
In same pan, saute shrimp in remaining butter over medium-high heat 2 minutes. Add garlic; cook and stir until shrimp turn pink, 1-2 minutes. Stir in mushroom mixture; heat through. Serve over linguini. Sprinkle with cheese and parsley.