use File::Spec::Functions qw( catfile );

sub get_files_in_dir {
   my ($dir_name) = @_;
   opendir(my $dh, $dir_name)
      or die("Unable to open dir \"$dir_name\": $!\n");
   return map catfile($dir_name, $_),
          grep -f,
          grep !/^\.\.?\z/,
          readdir($dh);
}

my $dir_name = '...';

# Get list of files.
my @files = get_files_in_dir($dir_name);

# Group files by customer.
my %files_by_cust;
foreach (@files) {
   my ($cust_id) = /^customer(\d+)\./
      or next;

   push @{ $files_by_cust{$cust_id} }, $_;
}

# Process each customer's files.
foreach my $cust_id (keys %files_by_cust) {
   # List of files is in @{ $files_by_cust{$cust_id} }.
   # ...
}
[download]

Updated: Added omitted call to opendir.

I would create automatically a zip for each customer (customerxxx.zip)containing his own files, grouping the entire set of files.

One approach (update: implemented by ikegami below) would be as follows:

Use opendir/readdir/closedir to find all the filenames, building a hash where the keys are the the distinct customer numbers (use a regexp to retrieve it from the filename) and the values are references to lists of filenames for each customer number.

When you've built the hash, iterate the keys (customers) where for each key you build a zip file (using say Archive::Zip) adding the files listed against that key to the archive.

You might even remove the source files at the same time if that's your preference.

-David

     
     @xmlFileNames=grep !/^\.\.?$/ && /\.xml$/,readdir(DIR);
The number of xml you get is the number of total customers.
[download]

   foreach my $customer (@xmlFileNames) {
         $customer =~ s/\.xml//g;
  system ("/usr/local/bin/unzip ${customer}.zip    ${customer}.xml  ${
+customer}.pdf ${customer}.xls");

   }
[download]

#!/bin/bash
for f in customer*.xml
do
  /usr/bin/zip ${f%xml}zip ${f} ${f%xml}pdf ${f%xml}xls;
done
[download]

thanks to everybody, very useful tips.

...but my platform is windows, how the grep?

#!/usr/bin/perl
use strict;
   use Archive::Zip qw( :ERROR_CODES :CONSTANTS );

my $some_dir = 'sql';

opendir(DIR, $some_dir) || die "can't opendir $some_dir: $!";
my @files = readdir(DIR);
closedir DIR;

@files = sort @files;

my $f2z;
foreach my $file (@files){
   if ($file=~/^\.$/){
      next;
   }
   elsif(-d $file){
      next;
   }
   else{
      my ($name,$ext) = split(/\./, $file);
      push(@{$f2z->{$name}}, $file);
   }
}

while (my($key, $value) = each(%{$f2z})){
   #print $key.", ".$value."<br />";

   my $zip = Archive::Zip->new();
   chdir($some_dir);
   foreach my $v (@{$value}){
   $zip->addFile( "$v" );
   }
   unless ( $zip->writeToFileNamed("$key.zip") == AZ_OK ) {
       die 'write error';
   }
}
[download]