use strict;
use warnings;
use Data::Dumper;

my $channel_name;

my %files_by_channel = (
            'ch1' => {
                     '00014' => '/foo/oradata/bar/foodb-lob01.dbf',
                     '00008' => '/foo/oradata/bar/foodb-index11.dbf',
                     },
            'ch2' => {
                     '00004' => '/foo/oradata/bar/tools01.dbf',
                     '00019' => '/foo/oradata/bar/foodb-data02.dbf',
                     '00003' => '/foo/oradata/bar/undotbs01.dbf'
                    },
);


my %rearranged;

foreach my $ch ( keys %files_by_channel ) {
    my $file_ref = $files_by_channel{$ch};
    foreach my $file ( keys %{$file_ref} ) {
        $rearranged{$file} = [ $ch, $file_ref->{$file} ]
    }
}

printf "%-10s %-15s %-40s\n", 'File#',  'Channel Name', 'File Name';
printf "%-10s %-15s %-40s\n", '-' x 10, '-' x 15,       '-' x 40;
printf "%-10s %-15s %-40s\n", $_, @{ $rearranged{$_} } 
    for sort keys %rearranged;