MacOS the UNIX (BSD) based Operating System used by Apple

macOS Catalina #

MacOS.10.15 will now use zsh as the default Login Shell and interactive shell across the MacOS Operating System. All newly created user accounts in MacOS.10.15 will use zsh by default. Bash will still be available, but Apple is signaling that developers should start moving to zsh on macOS.10.14 or earlier in anticipation of bash eventually going away in MacOS.

Apple hasn’t explained exactly why it’s making this change, but bash isn’t exactly a modern shell as it’s implemented in macOS, and a switch to something less aging makes a lot more sense for the company. Apple is stuck using version 3.2 of bash that has been licensed under GPLv2, as newer versions are licensed under GPLv3. Apple has kept clear of using GPLv3 packages in MacOS as the license is generally more restrictive to companies like Apple that sign their own code and it includes explicit patent grants

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