Put the oil into a large sauté pan with a lid and place over medium-high heat. Once hot, add the garlic, basil, tomatoes, olives, capers, and 1/2 teaspoon salt and continue to fry for 3-4 minutes, stirring frequently, until the tomatoes start to break down. Add the water and stir to mix thoroughly. Add the rosa harissa sauce, once boiling, decrease the heat to medium-low, cover the pan, and simmer for 10 minutes. Remove the lid and continue to cook for 4-5 minutes, until the sauce is thick and rich.
Meanwhile, fill a large pot with plenty of salted water and place it over high heat. Once boiling, add the linguine and cook according to the package instructions, until al dente. Drain well.
Return the pasta to the pot along with the harissa sauce and 1/8 teaspoon of salt.