Thank you for your reply.

I adapted my code according to your code and it works. However, I have another issue. It doesn't work with all XML files I have. the difference is that the one files has

and it works, while the other one has

and it doesn't work.

Moreover, the second file has the structure below.

Here is my code

#!/usr/bin/perl

use 5.010;
use strict;
use warnings;

use XML::LibXML;

my $new_values_file = shift;
open my $in, '<', $new_values_file or die "$new_values_file: $!";
chomp(my @new_values = <$in>);

my $dom = 'XML::LibXML'->load_xml(IO => *STDIN);

my $i = 0;
foreach my $alt_trans ($dom->findnodes('//file/body/group/unit/alt-tit
+le/otherTitle[@origin="title"]')) {
    print $alt_trans->to_literal();
    $alt_trans->removeChildNodes if $alt_trans->findnodes('text()');
    $alt_trans->appendText($new_values[$i]);
    $i++;
}
[download]

And one more question. Why in this file it doesn't work? Because there are blocks of <group> elements? Is my Xpath correct with this structure?

...
<group>
 <unit id="3Ojs1SLwMmEHK8mJ0_dc2:43”>
  <titleEN>{3&gt;19&lt;3}</ titleEN >
  <titleFR>{3&gt;19&lt;3}</ titleFR >
  <alt-title origin="tilte"><otherTitle/></ alt-title>
  <alt-title origin="price"><otherPrice/></ alt-title>
 </unit>
</group>
<group>
 <unit id="3Ojs1SLwMmEHK8mJ0_dc2:43”>
  <titleEN>{3&gt;19&lt;3}</ titleEN >
  <titleFR>{3&gt;19&lt;3}</ titleFR >
  <alt-title origin="tilte"><otherTitle/></ alt-title>
  <alt-title origin="price"><otherPrice/></ alt-title>
 </unit>
</group>
...
[download]