Pattern: Use of doubly nested parentheses
Issue: -
ShellCheck found doubly nested parentheses in an arithmetic expression. While the syntax for an arithmetic expansion is $((..)), this does not imply that parentheses in the expression should also be doubled. (x), ((x)), and (((x))) are all identical, so you might as well use only one layer of parentheses.
Example of incorrect code:
value=$(( ((offset + index)) * 512 )) Example of correct code:
value=$(( (offset + index) * 512 ))