Breadcrumbs give garlicky linguine with anchovies unexpected crunch.
Preheat oven to 350 degrees. Working in batches, process bread in a food processor until coarse crumbs form. Heat 1 cup oil in a large skillet over medium-high heat until hot but not smoking. Add whole garlic; cook until golden, about 2 minutes. Add breadcrumbs; stir to coat.
Transfer breadcrumb mixture to a rimmed baking sheet. Bake, stirring occasionally, until golden brown, about 12 minutes. Transfer to a baking sheet lined with paper towels; discard garlic.
Bring a large pot of water to a boil; add salt. Add pasta; cook until al dente. Drain, reserving 1 cup pasta water.
Heat remaining 1/2 cup oil in a large nonstick skillet over medium heat until hot but not smoking. Add minced garlic; cook until golden, about 2 minutes. Stir in anchovy fillets and chiles; cook, 2 minutes. Add pasta to skillet; toss to coat. Add lemon juice and all but 2 tablespoons parsley. Toss, adding up to 1 cup pasta liquid if pasta seems dry.
Season with pepper. Divide among serving dishes; top each serving with some of the breadcrumbs and lemon zest. Garnish with remaining parsley.