> 9. Always quote variable accesses with double-quotes. > - One place where it’s okay not to is on the left-hand-side of an [[ ]] condition. And the right-h

> 9. Always quote variable accesses with double-quotes. > - One place where it’s okay not to is on the left-hand-side of an [[ ]] condition. And the right-hand-side of a variable assignment. And the WORD in a case statement. (Not in the patterns, though). Plus a bunch of other single-token(?) contexts. I don't recommend relying on the context though, it's clever and makes it hard to verify that the script does not have expansion bugs.