The code as posted doesn't work. Where does $node_c come from?

If you want to fill a node regardless of whether it contains any text, don't use its text contents - as there can be none. Clean the node instead and add the new text: 

#! /usr/bin/perl
use strict;
use feature qw{ say };
use warnings;

use XML::LibXML;

my $xml = '<header>
   <id x_id="1">
      <a></a>
      <b></b>
      <c>NA</c>
   </id>
</header>';

print "Please specify node c content: ";
chomp( my $new_text = <STDIN> );

my $dom = 'XML::LibXML'->load_xml(string => $xml);
for my $node($dom->findnodes('(/header/id/b | /header/id/c)')) {
    $node->removeChildNodes;
    $node->appendText($new_text);
}
print $dom;

[download]

Or, try XML::XSH2:

open file.xml ;
for (/header/id/b|/header/id/c) set text() "YOUR TEXT HERE" ;
save :b ;

[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: XML replacenode by choroba
in thread XML replacenode by michael99

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