#!/usr/bin/perl --
use strict; use warnings;
use Path::Tiny qw/ path /;
my $pdf = path( '-/xy/-/02239_04_04_1989_PkW.pdf' );
print $pdf->basename, $/;
print $pdf->basename =~ m{^(\d+)_}, $/;
__END__
02239_04_04_1989_PkW.pdf
02239