use strict;
my $str = '<p data-entity-type="" data-entity-uuid="" style="text-align: center;"><span><img alt="image.jpg" data-entity-type="" data-entity-uuid="" height="349" src="image.jpg" width="620" /><span title="Click and drag to resize">•</span></span></p>
<p><img alt="image.jpg" data-entity-type="" data-entity-uuid="" height="349" src="image.jpg" width="620" /></p>
<html>
<head></head>
<body>
some text here...
<p><img alt="image.jpg" data-entity-type="" data-entity-uuid="" height="349" src="image.jpg" width="620" />
</p>
</body>
</html>\'
// Wanted result : <html><head></head><body>some text here...<img alt="julie-bishop.jpg" data-entity-type="" data-entity-uuid="" height="349" src="/sites/default/files/inline-images/julie-bishop.jpg" width="620" /></body></html>
';
my $regex = qr/<p(?:[^>]*|\r\n|\n)>(?:.*|\r\n|\n)(<img(?:[^>]*|\r\n|\n)>)(?:.*|\r\n|\n)<\/p>/p;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
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