Question

How do I make use of complex logical operations with egrep?

I can simply do, “egrep -v C abc.txt” to implement not of C and find that in abc.txt.

I can do “egrep A.*B abc.txt” to implement and of A and C to find that in abc.txt.

But how do I do something like,

A AND B (NOT C)

I googled around but couldn’t find a working solution.

Any help is much appreciated!

Answer 1

The simplest way would be to pipe the output of one grep into the input of another:

egrep A.*B <file> | egrep -v C

Mind you, that’s more of “A then B” than it is “A and B”. If you need more sophisticated matching logic I suggest you check out awk.