Blame me; I suspect Guido had the attached recently-posted Perl example
in mind. Note the 3rd line from the bottom ...
Tim Peters firstname.lastname@example.org
not speaking for Kendall Square Research Corp
$substitution = 'piece of substituted text';
print <<HERE1, <<'HERE2', <<`HERE3`;
this is a really big multi line string that
has embedded "double quotes" and 'single quotes'
and a $substitution
and this is another chunk
but $substitution is suppressed because of the
single quotes on 'HERE2'
echo "and here's yet another"
echo produced by shell command `echo SUBSTITUTION | tr A-Z a-z`
echo because of the backticks on HERE3