grep '^s\?[hk]\?[ei][ln][tlk]y\?$' /usr/share/dict/words | perl -MData::Dumper -ne '$p=\\%t;$p=\$$p->{$_}for/./gs;$$p=0;END{print Data::Dumper->new([\%t])->Terse(1)->Indent(1)->Sortkeys(1)->Useqq(1)->Dump()}' | less