If the matching tags aren't nested, it can be done like so
my $string = "<S>yada yada yada</S>";
print "Yes! $1\n" if $string =~ m{<S>(.*?)</S>};
### Here is an explanation of the regular expression
use YAPE::Regex::Explain;
print YAPE::Regex::Explain->new('<S>(.*?)</S>')->explain;
__END__
The regular expression:
(?-imsx:<S>(.*?)</S>)
matches as follows:
NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
----------------------------------------------------------------------
<S> '<S>'
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
.*? any character except \n (0 or more times
(matching the least amount possible))
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
</S> '</S>'
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------