Regex: match strings that don't match the submode

Question

Let's say I have a regex foobar expression, and I want to find all the lines in the document that do not match foobar. I can do it? How can I do it?

Answer 1

^(?!.*foobar.*).+$ 

With a multi-line option, matches an entire line that does not contain foobar.

Answer 2

The regular expression for your case might be this

 ^((?!foobar))$ 

edited by:

but if you want only grep then you can use the -v option:

 grep -v foobar