Correct me if I'm wrong, but in sh at least the $A is evaluated and replaced before the env A=, so a better example would be to write a shell script that echos $A and use that instead of echo
Inspired by the previous non-answers, I did that, and apparently you are right. So this is unrelated to the kind of command you use. This is even stupider than I thought: you assign before $A, but $A is still evaluated to the old value. This is comparable to the "valid" C 'int a = a;' code.
Thanks for pointing that out and resurrecting my faith in the human race as a by-product. After which a third non-answer arrived.
