my $_=$a;  say while s|[^/]+/*$||;

__END__
/aaaa/bbbb/cccc/dddd/
/aaaa/bbbb/cccc/
/aaaa/bbbb/
/aaaa/
/

##</code><code>##

my @dirs;
my $_=$a;  push @dirs, $_ while s|[^/]+/*$||;
say for reverse @dirs;

__END__
/
/aaaa/
/aaaa/bbbb/
/aaaa/bbbb/cccc/
/aaaa/bbbb/cccc/dddd/