Author: Stan Eisenstat
Subject: Re: [Cs323] Hi, why is this invalid?
Date: Saturday, 17 Oct 2020, 15:45:07

    > Message Posted By: Unknown
    >
    > [...@cobra hw3]$ /c/cs323/Hwk3/mcBash
    > (1)$ ${\}}
    > Invalid expansion

As stated in the specification:

  4. When mcBash detects any of the following errors:
     * ${ not followed by an alphanumeric or _
     ...
     it prints a one-line message to stderr and gives a new prompt ...

--Stan-