[bananskalhalk]

Seems to work in zsh too. Both bash and zsh are shells like c-shell ksh etc. Nowhere is it implied that shell-scripts are written for Bourne shell.

[arisudesu]

I am not familiar with zsh, but is it really interpreted by zsh? Because the script has #!/usr/bin/env bash in its shebang, isn't it executed by bash on your system, even if launched from zsh?

[bananskalhalk]

It seems to be very source-able in both bash and zsh. If you just executed it, it will run in bash.

They seem to have gone through some effort for this to be true.

[sambazi]

both bash and zsh are orders of magnitude more complex than sh or even ksh