find (\&checkfor, "D:/DOWNLOAD/DISTRBTN/I01/");
sub checkfor {
    if (-f $_) { print $File::Find::name."\n" };
}
[download]

I'm thinking a loop of some sort, but there is a gap of numbers.

You could still use a loop, e.g.

for my $n (1..22,50,60,70,80,97) {
    my $path = sprintf "D:/DOWNLOAD/DISTRBTN/I01/B%02d/", $n;
    if (-e $path) { 
        #... 
    }
}
[download]

use strict;
use warnings;
use File::Slurp qw(read_dir);

my $path = 'D:/DOWNLOAD/DISTRBTN/I01/B';
my @dirs = map { sprintf "$path%02d/", $_ } 1..22, 50, 60, 70, 80, 97;
for my $dir (@dirs) {
    my @files = grep { -f "$dir/$_" } read_dir($dir);
    # do something with files
}
[download]

Update: added grep to just get files.

well Perl has got this two cool functions (among others:)) :

opendir();
readdir();


so what you could do is:
use strict;
use warnings;
use File::Copy;

opendir (DIR,"./path") || die "$!";     # this opens the directory
foreach my $i(readdir DIR){
  next if (/\./g || grep{$_=~/$i/g}22..50);
  move("./path/$i", "/tmp/$i");   #   if (-e "./path/$i");
}
closedir DIR;
[download]

UPDATE:

my bad, tollic is right, so basically what you do is check if the var in question is a regular file or not:

next unless(-f "./path/$i" || !grep{$_=~/$i/g}22..50);

[download]

next if (/\./g);

That will skip all files and sub-directories which contain a literal dot in the name, such as 'file.txt'. It will not skip any directories which do not have a dot, such as 'junk'.

Another approach. You should be able to see how you could recurse into sub-dirs with the same idea. Path::Class.

use Path::Class ();

my $dir = Path::Class::Dir->new("D:/DOWNLOAD/DISTRBTN/I01/");

for my $file ( grep { not $_->is_dir } $dir->children )
{
    print $file, $/;
}
[download]

for dir in $(find /rootdir/101/ -type d -name "B??"); 
do find $dir -type f -exec rm '{}' \; ;
done;

# or to move elsewhere
# do find $dir -type f -exec mv '{}' /tmp/foundstuff/ \; ;
[download]

$ find /rootdir/101/ -type f -exec mv '{}' /tmp/foundstuff/ \;
[download]

Thank you all for your suggestions.