http://www.perlmonks.org?node_id=137321


in reply to (code) One-liner parses ippl log for suspicious packets

From perlre:
`(?<!pattern)' A zero-width negative look-behind assertion. For example `/(?<!bar)foo/' matches any occurrence of "foo" that does not follow "bar". Works only for fixed-width look-behind.
So, how about:
perl -ne 'print if /(?<!time)\(/' < ippl.log > ippl.noteworthy

-Blake