It follows the same convention as most programming languages that expose the argument list. Python’s sys.argv has the program name at index 0 and the first argument at index 1. C’s char **argv does the same: index 0 is the program name, index 1 is the first argument. So it stands to reason that Zsh’s $0 should be the program name and $1 should be the first argument…

…which, by the way, is exactly what Bash does as well.

That isn’t incorrect, but it’s not as important as people make it out to be. Linux isn’t certified as POSIX-conformant either.

People are way too stuck on POSIX regarding Fish specifically, but in shell scripting, POSIX compliance boils down to “can it run a pure sh script”. Bash is compliant. Zsh is partially compliant and needs to set an option to emulate sh. Fish uses a different syntax and is not compliant; if that is a problem, don’t execute sh scripts in Fish.

POSIX compliance for shell scripts was important in the 80s and 90s when the #! directive wasn’t as commonly implemented and every script might be executed by the user’s $SHELL instead. That is no longer the case as virtually every Unix-like system’s program loader supports #!.

It’s every person’s responsibility to make sure their mom’s (or dad’s (or other parental figure’s)) vibrator runs only secure, trusted software!

I miss cassettes and vinyl records only for nostalgia’s sake. Realistically, they were a BITCH to handle and store with questionable lifetimes and middling audio quality.