Need a hand with grep+regex

Question

I'm trying to find the set of words (if any) that contain two consecutive e’s, and also contains two y’s. But so far I tried following commands ,

grep -e '[y&y].*[ee]' -e '[y&y].*[ee]' words2.txt 
grep -e 'y.y' -e 'ee' words2.txt
grep -X '.*[y.y].*&.*[ee].*' words2.txt 
grep -X '.[*y.y].*&.[*ee].*' words2.txt

some of these commands gives either two y's or two consecutive e's, but don't give a word that contains both of these conditions. What should I do now?

Answer 1

I'm assuming your file looks something like this:

beeyy yeey open iee eey yeefy
funny reenydy jyyee

and is called words2.txt. Yes, the contents are kind of random. This will display the set of words containing consecutive ee and two y characters:

< words2.txt tr ' ' '\n' | grep 'ee' | grep 'y.*y'

This first ensures that each word is on its own line with tr, then greps for two consecutive e, then greps again for two (possibly non-consecutive) y. Since each grep is a filter, the end result is the set of words containing both consecutive ee and two y.

On my input, the result is:

beeyy
yeey
yeefy
reenydy
jyyee

Answer 2

Assuming you want exactly two ys and not at least two ys, with GNU grep if built with PCRE support:

grep -Pow '(?=\w*y\w*y)(?!\w*y\w*y\w*y)\w*ee\w*'

Or with ast-open grep (2014-01-26 or newer):

grep -Xow '\w*ee*\w*&\w*y\w*y\w*&(\w*y\w*y\w*y\w*)!'

If you also want at least one sequence of exactly two es (and not 3 or more), that is for instance match on eeyy or eeyyeee but not eeeyy), with GNU grep -P:

grep -Pow '(?=\w*y\w*y)(?!\w*y\w*y\w*y)\w*(?<!e)ee(?!e)\w*'

Answer 3

Just a variant of Fox's answer:

grep -Po '\w*ee\w*'  words.txt | grep 'y.*y'

if you want exactly 2 ys:

... | grep -v 'y.*y.*y'