use \1 for the first, \2 for the second, and so on.
Outside the match use "$" instead of "\". (The
\<digit> notation works in certain circumstances outside
-the match. See the warning below about \1 vs $1 for details.)
+the match. See L</Warning on \1 Instead of $1> below for details.)
Referring back to another part of the match is called a
I<backreference>.
X<regex, capture buffer> X<regexp, capture buffer>
$pattern =~ s/(\W)/\\\1/g;
-This is grandfathered for the RHS of a substitute to avoid shocking the
+This is grandfathered (for \1 to \9) for the RHS of a substitute to avoid
+shocking the
B<sed> addicts, but it's a dirty habit to get into. That's because in
PerlThink, the righthand side of an C<s///> is a double-quoted string. C<\1> in
the usual double-quoted string means a control-A. The customary Unix