Another one I can't seem to solve : all greek letters with 5 unique letters (meaning that each letter only appears once).
my solution :
egrep '(.)([^/1])([^/1/2])([^/1/2/3])([^/1/2/3/4])' greek.txt
So What I think I am saying :
match any first character
every consecutive character can't be any of the previous patterns
But what comes out :
alpha gamma delta epsilon theta kappa lambda omicron sigma upsilon omega
Alpha, gamma, they have characters that are not unique. Any hints or tips on what I am doing wrong ?