macOS Catalina : zsh by default, Python and Ruby impaired

It is a small revolution : macOS abandons the shell Bourne-Again (bash), the command interpreter of the most GNU/Linux distributions, for the benefit of the Z shell (zsh). This shell modern, in the sense that it was designed in the early 1990s, can be seen as an extended version of bash.

Zsh in the Terminal on macOS Catalina.

Zsh is distinguished by its mechanism completely controls evolved, the correction of typos, its support of advanced models, glob, or even its module system, adding functions. This shell is very popular among the developers is supported by a very active community, which offers many themes and plug-ins on the site Oh My zsh.

The new shell is enabled only on new machines, or after a “clean” installation of macOS Catalina. After an update from macOS, Mojave, bash will remain the shell by default, but you can switch to zsh by entering the command chsh -s /bin/zsh. Apple dedicates a technical data sheet to this transition.

Note that macOS Catalina is always included with Python 2.7.10, Ruby 2.6.0p0, and Perl-5.18.4. These runtimes are provided only for compatibility with old software “, and will be removed in a future version of macOS. You will have to install them separately, for example with Homebrew but Homebrew application itself Ruby, its installation procedure will have to be modified).