Looking for a freeware text search utility

A few times over the last few years I have had cause to look through large log files for unusual entries, and as I'm not looking for something specific, it would be handy to be able to filter out all ordinary lines and see what is left.

As an example, I have a 2Mb log file from a web server, and each line stores the date, time, source IP address, URL requested and result code.
We have an external monitoring system periodically checking the status of pages on the site to ensure their availability and integrity.
This causes the log files to be much greater than they would normally be due to "genuine" traffic, and filled with requests from the same source IP address.

What I'd like to do is filter out all lines with this source IP address in - but as the lines are all unique (date, time, URL change) I can't just do a search & replace with a blank field.


Does anyone know of any freeware Windows utility that would do what I want?

Unfortunately I can't think of suitable search phrases to enter in Google to make it find one for me :p
I guess it's a kind of "anti-grep" utility?

Import into Excell, Sort and cut?

Okay, I guess I could import as CSV (the logs happen to be delimited with commas) and sort on the IP field, then highlight the (ir)relevent records and delete them...

Thanks, I must admit I didn't consider that - and if I need them in natural order I can re-sort on the date field.

Was kind of hoping for a tiny tool to open the files directly and work with them, but whatever works I guess :D

Cheers!