Casings

noun

1. That which encloses or encases.

   "Some people like to split the casing of a sausage before cooking so it doesn't burst."

2. The decorative trim around a door or window.
3. A metal pipe used to line the borehole of a well.
4. The collective states of upper and lower case letters.

   "The replacement string should have the same casing as the matched text."