G'day froodley,

Welcome to the Monastery.

There's three sections of perlop where you'll find that information. I've listed them below with some notes about the special delimiters they reference; however, I make no guarantee I've got them all. Also, my notes are brief and may contain oversimplifications: the doco has details.

Quote and Quote-like Operators

• See the table, at the start of this section, for quoted strings that don't interpolate when the delimiter is a single-quote. The remaining two sections have further details.

Regexp Quote-Like Operators

• qr{...} doesn't interpolate with single-quote delimiter.
• m{...} doesn't require the 'm' with forward-slash delimiter.
• m{...} only matches once with question-mark delimiter.
• s{...}{...} doesn't interpolate with single-quote delimiter.

Quote-Like Operators

• qx{...} doesn't interpolate with single-quote delimiter.
• <<EOF and <<"EOF" interpolate; <<'EOF' doesn't

In addition, take a look at split for some special cases of the pattern, e.g. ' ' vs. / /.

And the last one I can think of is setting $/ (the input record separator) to "" for paragraph mode. See perlvar for details of that one.