UPDATE:a warn to you all: do not use regexes against XML! they (and you too) loose.

In the spirit of more then one way I present an XML::Twig solution.
I'm sure there is a more elegant way to do it, anyway.
#!/usr/bin/perl

use strict;
use warnings;
use XML::Twig;

my $twig= XML::Twig->new(
                        pretty_print => 'indented',
                        twig_roots    => { 'tm' => 1 },
                        twig_print_outside_roots => 1,
                        twig_handlers => {   tm=>sub{my $text = $_->te
+xt(); $_->cut();print $text;  },
                        },
);
$twig->parse('<?xml version="1.0"?><stats><tm tmclass="ibm" tmowner="I
+BM Corporation" tmtype="reg" trademark="AIX">AIX</tm></stats>');

[download]
hth
L*

UPDATE2: i'm not sure to understand your case but maybe this handler is what you need to print only one time te text: 
#declare a global:
my $only_one=0;

#same as before, then:
twig_handlers => {   tm=>sub{my $text = $_->text();   $only_one ? $_->
+cut()  : ( $_->cut() and print $text and $only_one++ ) },

__DATA__
<?xml version="1.0"?>
                <stats>
                  <tm tmclass="ibm" tmowner="IBM Corporation" tmtype="
+reg" trademark="AIX">AIX</tm>
                  <tm tmclass="ibm" tmowner="IBM Corporation" tmtype="
+reg" trademark="AIX">AIX</tm>
                  <tm tmclass="ibm" tmowner="IBM Corporation" tmtype="
+reg" trademark="AIX">AIX</tm>
                </stats>'

__OUTPUT__
<?xml version="1.0"?>
                <stats>
                  AIX


                </stats>

[download]
There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

In reply to Re: Replacing an XPath node with the value of its content TIMTOWTDI by Discipulus
in thread Replacing an XPath node with the value of its content by stylechief

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