Can't call method "text" on an undefined value at IDOCXML_parse2.pl li
+ne 27, <$list> line 1.
 at IDOCXML_parse2.pl line 23
 at IDOCXML_parse2.pl line 23
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#!/usr/bin/perl
use warnings;
use strict;

use Text::CSV_XS;
use XML::Twig;

my $listfile = shift;
open my $list, '<', $listfile or die $!;
while (my $xmlfile = <$list>) {
    chomp $xmlfile;

my $twig = XML::Twig->new(
    twig_handlers => {
        'EDI_DC40' => \&process_EDI_DC40,
        },
    );

my $csv = Text::CSV_XS->new({
'sep_char'    => "|",
});

$twig->parsefile($xmlfile);
sub process_EDI_DC40 {
    my( $twig, $thingy ) = @_;

    my @values = map { $thingy->first_child( $_ )->text }
        qw(DOCNUM MESTYP SNDPRN RCVPOR RCVPRN);

    $csv->say( *STDOUT, \@values );
    }

}
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Somewhere in the data, there's an EDI_DC40 element that doesn't have all the child nodes. You need to check whether the child exists before calling a method on it:

    my @values = map {
        my $ch = $thingy->first_child( $_ );
        $ch ? $ch->text : ""
     } qw( DOCNUM MESTYP SNDPRN RCVPOR RCVPRN );
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Also, as I mentioned, you probably don't need to create a new Twig and CSV objects for each file. Declaring the sub inside the loop makes no sense, either.

#!/usr/bin/perl
use warnings;
use strict;

use Text::CSV_XS;
use XML::Twig;

my $csv = 'Text::CSV_XS'->new({
    sep_char => '|',
});

sub process_EDI_DC40 {
    my ($twig, $thingy) = @_;

    my @values = map {
        my $ch = $thingy->first_child( $_ );
        $ch ? $ch->text : ""
    } qw( DOCNUM MESTYP SNDPRN RCVPOR RCVPRN );

    $csv->say(*STDOUT, \@values);
}

my $listfile = shift;
open my $list, '<', $listfile or die $!;

my $twig = 'XML::Twig'->new(
    twig_handlers => {
        EDI_DC40 => \&process_EDI_DC40,
    },
);

while (my $xmlfile = <$list>) {
    chomp $xmlfile;
    $twig->parsefile($xmlfile);
}
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($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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Thanks, that works like a charm! One last question - I'm also trying to prefix every line in the output pipe separated file with this text "XML". I tried this, on the while loop right before the chomp, but the substitution isn't working as expected.

$xmlfile =~ 's/^/XML|/' ;
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Where do i insert the above line in the code for the prefixing to work?

while (my $xmlfile = <$list>) {
$xmlfile =~ 's/^/XML|/' ;
chomp $xmlfile;
    $twig->parsefile($xmlfile);
}
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