Although it can technically be made of a combination of any finely chopped ingredients, hash is often a mixture of beef (often leftovers of corned beef or roast beef), onions, potatoes, and spices that are mashed together into a coarse, chunky paste, and then cooked, either alone, or with other ingredients.
In many locations in the U.S., corned beef hash is served primarily as a breakfast food on restaurant menus and home cuisine, often served with eggs and toast (or biscuits), and occasionally fried potatoes (hashbrowns, home fries, etc). The dish is usually known as corned beef hash with eggs, or corned beef hash & eggs. Alternatives of the dish use roast beef hash.
Alternatively, in the southern United States hash is a blend of leftover pork from a barbecue mixed with barbecue sauce and served over rice. It is a common side dish at barbecue restaurants and pig pickins in South Carolina and Georgia.
In Denmark hash is known in Danish as "biksemad" (roughly translated, "tossed together food"), and it is a traditional leftover dish usually served with a fried egg, bearnaise sauce, pickled red beet slices and ketchup. The meat is usually pork, and the mixture is not mashed together into a paste, but rather the ingredients are coarsely diced and readily discernible in its cooked form.
In Malaysia a similar dish is called "bergerdil". It mainly consisted of minced meat, potatoes, and onions. It is then fried until brown