Re: Tr: Problem with grep v2.5.1

[Micah Cowan]

Simon Nieux wrote:
>> Hi,
>>
>> I use the grep utility intensively. It's a very useful software though it 
>> seems there's a problem...
>>
>> wget can generate log file.
>> I wanted to display only some specific lines with 3 extra lines above them 
>> from this log file.
>> Then, I wrote the following command :
>>     grep -B 3 "\.\.\.[0-9]\{3\}" wget.log
>> It works very well.
>> Then, I wanted to exclude lines with the string "...200" and the 3 lines 
>> above each.
>> So, I wrote the following command :
>>     grep -B 3 "\.\.\.[0-9]\{3\}" wget.log | grep -v -B 3 "\.\.\.200"
>> It doesnt work at all !
>> In fact, it removes only the last line who match from the precedent response 
>> but leaves the 3 lines above.
>> And surprisingly it leaves all the other lines who match...
>>
>> Is it the user who does wrong or the software ?

My understanding is that -B is meant to _include_ N lines of context
from before matches, not exclude them. What's going on is that the other
 ...200 lines are getting included because they are part of the -B
context of the lines that follow them and match the negative of ...200.

You might need to use awk or similar to do what you desire.

-- 
Micah J. Cowan
Programmer, musician, typesetting enthusiast, gamer...
http://micah.cowan.name/