Try this 

use strict;
my $input='
This is sample <This is sample text>
This is sample &lt;This is  sample text <a>this is sample text</a> sam
+ple text >
';

my @arr=$input=~m#&lt;[^<>]+(?:<a>.+?</a>[^<>]*)?>#g;
local $"="\n";
print "\n@arr";

[download]

Output 

&lt;This is sample text>
&lt;This is  sample text <a>this is sample text</a> sample text >

[download]

In reply to Re: encode HTML entities with a regexp by gopalr
in thread encode HTML entities with a regexp by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
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