Ex: Find words in "words.txt" with at least three a or A (both capital and small) letters. (Hint: You should probably use cat command, then, feed its output into grep command.)
I have tried some ways but I found like ___sss__, eee___.
My list:
Ababdeh
Ababua
abac
abaca
abacate
abacay
I have to find:
Ababua
abaca
abacate
abacay
Could you help me please?
Use a capturing group and backreferences.
grep -Ei '(.).*\1.*\1' words.txt
If there is a certain letter to look for, let's say a, that's easier.
grep -i 'a.*a.*a' words.txt