[solved] grep "this but not followed by one of these"

[toralf]

I'd like to ask for a single grep pattern which satisfies the condition to grep for all lines in a file containing string "foo" , if "foo" is not followed by "bar" or "bla".
So this should match : "prefix foo mampf postfix", but this not : "prefix foo bar postfix"

[John R. Graham]

Build grep with the pcre USE flag as you need the "negative lookahead" feature it provides. Then your regex is straightforward:

[toralf]

[khayyam]

toralf ...

[John R. Graham]

Two problems with my regex:

1. It doesn't match foo at the end of a line.
   
2. It doesn't take into account the possibility of non-space whitespace.

Solutions left as an exercise.

- John
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[toralf]

Hhm, so this is not the solution till now :

[John R. Graham]

You have an unescaped slash in that string. Take care with your escaping of characters that might have meaning in a regex context.

- John
_________________
I can confirm that I have received between 0 and 499 National Security Letters.