This program lets you search your Unix dictionary with a regex (PCRE).
Want to see words that have more than two vowels in a row? Try this:
$ dict -S '[aeiou]{3,}'
-S gets rid of the default behavior of matching a pattern from start. In regex terms, -S removes an implicit ^ anchor.
-f makes dict match the pattern at the end of the word.
-i turns on case-insensitivity.