use strict;
my $str = '<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>
<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>
<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>
<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>
<br><br>
sample text
<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>
<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>
more text
<li class="list-item">aewfaffjpiowfj: apeifjeawpfioj</li>';
my $regex = qr/<li [^>]*>.*<\/li>/p;
my $subst = '';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html