Complex sentence: Compared to languages such as bash, csh, and Perl, Expect has a different twist, and is sometimes challenging to remember when a variable must be prefixed with a "$", and when it is not.
Split into simpler sentences: Compared to languages such as bash, csh, and Perl, Expect has a different twist. It is sometimes challenging to remember when a variable must be prefixed with a "$", and when it is not.