Knowledge Warehouse

Bash provide developers a comprehensive reference on their website, but it is quite technical and dry [7]. A better introduction is provided by tutorials like the still-valid Advanced Bash Scripting Guide [8].

For Zsh users, the official documentation is the first place to go [9]. The fish developers offer a detailed tutorial, as well as a reference on their website [10].

Conclusions

Bash, fish, and Zsh offer a similar range of functions, but they differ in many details. These dissimilarities are especially present in the syntax of the control structures, which means that only extremely simple scripts run without changes in a different shell.

If you want to use a script on as many systems as possible, there is no alternative to Bash. It is normally preinstalled and has the biggest user base. If you have problems or questions, you can usually find help quickly on the Internet.

As for interactive command-line operations, many users express a preference for Zsh or fish because of their advanced autocompletion, enhanced configuration options, and other user-friendly features.

If portability does not play a role or is just a minor concern, the best approach is to try all three shells and use the one that works best for you. For example, if you only launch programs from the command line, fish's automatic suggestions could save you quite a bit of typing.