OK, so I looked at XML::Twig, and it looks like it should do what I need. My problem is, when I use the XPaths I'm being provided, I get errors.. for example running this against my example XML file.

#!/usr/opt/perl5/bin/perl -sw

use XML::Twig;
my $twig = XML::Twig->new();
$twig->parsefile($xmlfile);
my $root = $twig->root;
foreach my $i ($root->get_xpath('substring(//OLifE/Party[@id=//OLifE/R
+elation[RelationRoleCode/@tc=8]/@RelatedObjectID]/Person/First
Name, 1, 30)')) {
   print $i->{att}->{InvType};
   foreach my $j ($i->get_xpath('../InvCounts/InvCount')) {
      print " " . $j->{att}->{Count};
   }
   print "\n";
}
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the result is this

./twigs.pl -xmlfile=a2b9f375-51fe-41a1-86ab-069561517890.xml
error in xpath expression substring(//OLifE/Party[@id=//OLifE/Relation
+[RelationRoleCode/@tc=8]/@RelatedObjectID]/Person/FirstName, 1, 30) a
+round substring(//OLifE/Party[@id=//OLifE/Relation[RelationRoleCode/@
+tc=8]/@RelatedObjectID]/Person/FirstName, 1, 30) at ./twigs.pl line 7
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So, I guess I don't understand how I would use the XPaths I've been provided. Do I have to find the attributes they referecne first, and then substitute that into the related entry in the XPath?

You've been given

//Party[@id=//Relation[child::RelationRoleCode[@tc='37']]/@RelatedObje
+ctID]/Producer/CarrierAppointment/CompanyProducerID
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as an XPath expression. Why do you think you need to wrap substring(...) around that? What is your goal here?

Maybe start out with the simple XPath expressions, find out what XML::Twig returns and then look at how you get from a node to the values you really want.

The code I used with the substring was actually the third example of XPath provided in my original post, and as provided to me by the vendor included the substring function. I am assuming based on the complete XPath provided "substring(//OLifE/Party[@id=//OLifE/RelationRelationRoleCode/@tc=8/@RelatedObjectID]/Person/FirstName, 1, 30)" they are looking in this instance for the first 30 characters of a person's first name.

Now, I took your suggestion to heart, and using the first XPath "//Party[@id=//Relation[child::RelationRoleCode@tc='37']/@RelatedObjectID]/Producer/CarrierAppointment/CompanyProducerID " and resolving all the subqueryies I get it to run, however, not return any values.. although I have to admit, looking at the sample XML file, I'm not sure I totally understand where the data is supposed to come from, so I'm not sure I'm doing it correctly.

here is the modified script with the expanded XPath as I believe it should be, again I'm not sure I did it correctly since I'm very new to XML.

#!/usr/opt/perl5/bin/perl -sw

use XML::Twig;
my $twig = XML::Twig->new();
$twig->parsefile($xmlfile);
my $root = $twig->root;
foreach my $i ($root->get_xpath('//Party/Relation_daf1bb84-658a-4bad-a
+ff7-86d5fc755101/Party_2d205fbf-cadd-4475-9d51-a8a8aea1c625/')
) {
   print $i->{att}->{InvType};
   foreach my $j ($i->get_xpath('../Producer/CarrierAppointment/Compan
+yProducerID')) {
      print " " . $j->{att}->{Count};
   }
   print "\n";
}
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when I run it I get nothing. Which at least isn't an error.

any ideas would be appreciated.

I don't know what you are trying to extract but here's a simple example to get you started

#!perl
use strict;
use XML::Twig;

my $twig = XML::Twig->new();
$twig->parsefile('txlife.xml');
my $root = $twig->root;

my @nodes1 = $root->get_xpath('//Holding');
for my $hold (@nodes1){
  print "\nId = ".$hold->att('id')."\n";
  my @nodes2 = $hold->get_xpath('Policy/KeyedValue/KeyValue');
  for my $_ (@nodes2){
    print $_->prev_sibling_text." = ";
    print $_->text."\n";
  }
}
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Ouput should be

Id = Holding_aa2b0594-77d6-4264-b277-0218e852cb36
AccountType = Individual
CheckIndicator = No
1035ExchangeIncluded = No
SponsorName = InsCompany

Id = Holding_f2cfb5bd-6009-4bf2-95a0-686cb69a3b7a
OldProductType = 401K
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poj

I had to tweak it just a bit... for some reason I was getting the error Can't use global $_ in "my" at ./twig3.pl line 15, near "my $_ " and I added passing the filename as a command line variable.

#!/usr/opt/perl5/bin/perl -sw

# use strict;
use XML::Twig;

# my $xmlfile=@ARGV;
my $twig = XML::Twig->new();
$twig->parsefile($xmlfile);
my $root = $twig->root;

my @nodes1 = $root->get_xpath('//Holding');
for my $hold (@nodes1){
  print "\nId = ".$hold->att('id')."\n";
  my @nodes2 = $hold->get_xpath('Policy/KeyedValue/KeyValue');
  for $_ (@nodes2){
    print $_->prev_sibling_text." = ";
    print $_->text."\n";
  }
}

./twig3.pl -xmlfile=a2b9f375-51fe-41a1-86ab-069561517890.xml

Id = Holding_a344e55a-1471-4c90-aa94-481b434a5b12
AccountType = UTMA_UGMA
CheckIndicator = No
1035ExchangeIncluded = No
SponsorName = Transamerica

Id = Holding_8f6e6000-6cc5-4e7a-b5e8-3acd2ee03468
OldProductType = 401K
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this will get me on my way! Thank you, you help is much appreciated. Also a note, I've discovered during this adventure that the file is an ACORD standard file https://www.acord.org/standards/downloads/Pages/PCSPublic1.aspx for what its worth. Now I just need to figure out how to dissect the sub-attributes and insert them into the XPath.

Again, thank you.