I have nothing at all against POSIX, but unless one is running HP-UX, Solaris or an illumos-based OS like SmartOS, POSIX compliance is spotty at best in other o

I have nothing at all against POSIX, but unless one is running HP-UX, Solaris or an illumos-based OS like SmartOS, POSIX compliance is spotty at best in other operating systems. For this reason, the safest thing to do is write code for either the original Bourne shell, or ksh. Programs written in ksh are the most portable across systems, moreso since other systems have it too. And to top it all off, ksh sets the standard for POSIX, especially ksh93.