- SC2006: Use $(..) instead of deprecated `..`
- SC2086: Double quote to prevent globbing and word splitting.
- SC2046: Quote this to prevent word splitting.
- SC2012: Use find instead of ls to better handle non-alphanumeric filenames.
- SC2004: $ on variables in (( )) is unnecessary.
- SC2016: Expressions don't expand in single quotes, use double quotes for that.

Signed-off-by: Tim Niemeyer <[email protected]>
Reviewed-by: Jan Kraus <[email protected]>
- fixed typo in same line
Signed-off-by: Tobias Klaus <[email protected]>