Backward compatibility of shell scripts
"Will it work" has two aspects here:


will executing the binary work?
is bash capable of running the script as such.


The example looks fairly basic as far as shell scripting is concerned. So yes, it should work with previous OSX versions of bash. It would (as long as Something is installed in /usr/local/bin) even work in quite old versions of the Bourne Shell (/bin/sh) on various Unix systems.