On Wed, Sep 16, 2020 at 07:37:01PM +0200, Christian Weisgerber wrote:
> This one had me puzzled.  How did the while condition ever work?
> Apparently, variables are expanded without '$' for arithmetic(!)
> comparisons inside [[ ... ]] and in our (k)sh this behavior accidentally
> leaks out to [ ... ].
From ksh(1):

   Arithmetic expressions
        Integer arithmetic expressions can be used with the let command, inside
        $((..)) expressions, inside array references (e.g. name[expr]), as
        numeric arguments to the test command, and as the value of an assignment
        to an integer parameter.

`test' is `[', so that is known^Wdocumented behaviour.

> Mark the variables as "local" while here.  Actually, "local" isn't
> part of the POSIX shell language, but it's used pervasively in these
> scripts and seems widely supported in practice.
OK kn