Unfortunately, taken as a whole (eg, not just blithely ignoring POSIX, or systems that don't support it, or systems that don't support long options), portable s

Unfortunately, taken as a whole (eg, not just blithely ignoring POSIX, or systems that don't support it, or systems that don't support long options), portable shell is a big mess. Keeping it simple would be nice, but may not be possible, depending on your goals ("make everything as simple as possible, but no simpler"). So you want to write some script that will only ever run on systems with GNU utilities installed, and you never ever plan on porting it? Fine. Just do the world (and yourself) a favor and be aware of and admit that fact upfront. And if you're going to break POSIX compatibility anyway, it would be nice if you use the long options for better readability.