 Use $(..) instead of legacy `..`
 Use $(..) instead of legacy `..`

Backtick command substitution `STATEMENT` is legacy syntax with several issues.

1. It has a series of undefined behaviors related to quoting in POSIX.
2. It imposes a custom escaping mode with surprising results.
3. It's exceptionally hard to nest.
pimusicbox/pimusicbox,pimusicbox/pimusicbox,pimusicbox/pimusicbox