First, get a list of all the files. Below this is the __DATA__ segment, but for your app, use opendir, readdir.

Make a hash of array keyed upon the "number" of the file (the digits before the '.' or '_').

Then for each new numbered "append" file, open a file handle and copy the files to the new file. 

#!/usr/bin/perl -w
use strict;

my %new_files;

while (my $filename = <DATA>) 
{ 
   chomp $filename;
   my $num = ($filename =~ /^(\d+)/)[0];  #just the first digits
   push (@{$new_files{$num}},$filename);  
}

foreach my $new_file (keys %new_files)
{
   print "open file for ....$new_file"."_AppendFile.txt\n"; #your code
   print "put these files in there: \n"; #you have to make a copy loop
   print "@{$new_files{$new_file}}", "\n";
   print "\n";
}

=prints:
open file for ....1_AppendFile.txt
put these files in there: 
1_ABC.txt 1_XYZ.txt

open file for ....3_AppendFile.txt
put these files in there: 
3_ABC.txt

open file for ....2_AppendFile.txt
put these files in there: 
2_ABC.txt 2.XYZ.txt

open file for ....5_AppendFile.txt
put these files in there: 
5.XYZ.txt
=cut
__DATA__
1_ABC.txt
2_ABC.txt
3_ABC.txt
1_XYZ.txt
2.XYZ.txt
5.XYZ.txt

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In reply to Re: Appending multiple files into one or more files by Marshall
in thread Appending multiple files into one or more files by iamravikanth

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