I think you need to decode first and then encode. 
#! /usr/bin/perl

use strict;
use warnings;
use HTML::Entities;

my $str = "TEST&TEST;A&E&an HTML--- string - <© TVS&
+gt;";
my $decoded = decode_entities($str);
my $encoded = encode_entities($decoded);

print $encoded;

__DATA__
TEST&TEST;A&E&an HTML--- string - <© TVS
+>

[download]
TEST&TEST;A&E&an HTML--- string - <© TVS>

In reply to Re: replace & by wfsp
in thread replace & by sandy1028

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
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  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
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  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
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    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
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