[piaste]

Given that 'alias' is in POSIX, would a combination of

(a) the hypothetical non-argv0 busybox being discussed, and

(b) a POSIX shell of the maintainer's choice, with built-in aliases for 'ls=busybox ls'

be sufficient to make the system POSIX complaint?

[blenderob]

aliases are not inherited by subprocesses unfortunately! so the alias solution would not work when a shell script launches other shell scripts. It wouldn't work in a wide range of other scenarios too like Makefiles, bespoke build tools, binary executables that do execve("/usr/bin/cmp", ...) etc.

[yellowapple]

In addition to the already-raised issue of subprocesses not inheriting aliases, I'd also be worried about aliases inherently being specific to particular shells. I'd hate to have to redefine those aliases for sh, csh, zsh, fish, and Lord knows what else. It'd also be an issue for invoking those tools without going through a shell in the first place - as is common for programs launching external programs as subprocesses.

That's indeed why I personally don't use shell aliases at all, instead opting for actual shell scripts in my $PATH. Those will work no matter what shell I'm using (if any).