ormaaj 1445406984 learn Bash version 3 - the version distributed with Mac OS X - is long unmaintained and showing its age. It omits numerous critical bug fixes and enhancements including associative array support. If you can't upgrade due to the license or for other reasons, you should immediately begin planning migration to ksh93, zsh, or mksh. All 3 are maintained, non-copyleft free software with substantial bash ormaaj 1445407182 forget ormaaj 1445407409 learn Bash version 3 is long unmaintained and showing its age. It omits numerous critical bug fixes and enhancements including associative arrays. If you can't upgrade for licensing or other reasons, you should immediately begin planning migration to ksh93, zsh, or mksh. All 3 are maintained, non-copyleft free software with substantial bash feature parity.