--[no]alias    [don't] use the alias list in the ini file (default noalias)

documentclass[article]{memoir}
usepackage{listings}
lstset{language=Perl,stringstyle=slshape}

begin{document}
begin{lstlisting}
my $commentA =   "Please, don't do this";
my $commentB =   "But do this";

print <<HERE;
Please, don't do this
But do this
HERE

my $commentC =   "Please, don't do this";
my $commentD =   "But do this";
end{lstlisting}
end{document}