$ ksh << END_OF_KSH
> perl << END_OF_PERL
> my $foo = qq{ bar \n };
> print qq{ FOO=$foo };
> END_OF_PERL
> END_OF_KSH
$ echo $FOO

$

##</code><code>##

$ echo "$foo"

$ echo "\$foo"
$foo
$ echo << ECHO
$foo
ECHO

$ echo << ECHO
\$foo
ECHO

$ echo << ECHO
\\$foo
ECHO
\
$