Created SC2322 (markdown)

SC2322.md

@@ -0,0 +1,24 @@
+##  In arithmetic contexts, ((x)) is the same as (x). Prefer only one layer of parentheses.
+
+### Problematic code:
+
+```sh
+value=$(( ((offset + index)) * 512 )) 
+```
+
+### Correct code:
+
+```sh
+value=$(( (offset + index) * 512 ))
+```
+### Rationale:
+
+ShellCheck found doubly nested parentheses in an arithmetic expression. While the syntax for an arithmetic expansion is `$((..))`, this does not imply that parentheses in the expression should also be doubled. `(x)`, `((x))`, and `(((x)))` are all identical, so you might as well use only one layer of parentheses.
+
+### Exceptions:
+
+This is a stylistic suggestion. If you prefer keeping both parentheses, you can [[ignore]] this message.
+
+### Related resources:
+
+* Help by adding links to BashFAQ, StackOverflow, man pages, POSIX, etc!