Re: [Help-bash] Arithmetic evaluation / expansion question

[Greg Wooledge]

On Wed, Oct 10, 2018 at 12:47:05PM -0400, Bruce Hohl wrote:
> Are strings also evaluated to zero within $(( ))?
> 
> $ pd=abc
> $ echo $pd
> abc
> $ echo $((pd))
> 0

As Andy said, things that can be parsed as variable names are treated
as variable names in arithmetic contexts.  What he didn't mention was
that bash does this *recursively* until it gets to an integer, or to
something that can't be parsed as either an integer or a variable name.

wooledg:~$ a=b b=c c=d d=e e=f f=42; echo $((a))
42