Crossword helper

bash

awk 'length==6' /usr/share/dict/american-english | grep "^[a-zA-Z]a[a-z][a-z][a-z]t"

Find all words in the American English dictionary with a length of 6 charachter that start with either a lower or upper case character, an "a" in the second position, three lower case characters and a "t" at the end. I'm quite sure the regular expression could be optimized (the redundant [a-z] bothers me).