Using egrep to match patterns
I am hoping to get some help with this exercise; I need to make regular expressions for collections with egrep to solve it.
Given are a lot of lines with numbers and spaces
ig: 222 266222 266
6444 44555 577
To be a part of the collection, the sum of the numbers two places before the space and to places after have to be 8.
222 266222 266 -> 2+6=8
I have to do this for these combinations: 2 and 6, 5 and 3
So far I have this: egrep '(2. .6|6. .2|3. .5|5. .3)'
But with this expression, as long as one space matches the expression it becomes part of the collection, so I can still end up with 7. .7 at another space for example.
I need this expression to match for every possible space.
Thanks in advance