In 4-quart Dutch oven, cook linguine as directed on package. Drain; return to Dutch oven and cover to keep warm.
Meanwhile, in 10-inch nonstick skillet, melt butter with oil over medium heat. Add garlic; cook and stir 1 minute. Add bell pepper, onions, parsley and flour; cook and stir 1 minute. Gradually stir in milk until well blended. Heat to boiling, stirring constantly. Cook 6 to 10 minutes, stirring frequently, until sauce is bubbly and thickened.
Remove skillet from heat. Stir in basil, oregano and salt. Pour sauce over linguine; toss gently to coat. Sprinkle with cheese.