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grep throws in dashes?

 
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# 1  
Old 04-25-2007
grep throws in dashes?
Hey guys,

I'm trying to grep for two things out of a file and I got that working but why is it randomly throwing "--" in the output? Is there a simple way to get rid of them? It only seems to do it when the line above what im looking for has numbers in it.

Code:
$ egrep -i -B 1 'port-name|description' in.txt
127.0.0.1
description
--
127.0.0.2
description
--
127.0.0.3
description
helpme
port-name
yay
port-name

# 2  
Old 04-27-2007
See if this helps??
Hi,
I've seen something similar to this while using "gnu grep". If you simply grep for something, only those lines containing the search-pattern will be displayed. But if u issue "gnu grep -1 'search-pattern' file", you will get the lines immediately before and after the line containing the search-pattern.

In your case, it gives the line just before the line containing search-pattern, i guess.

There is a chance that your "egrep" may be aliased to "gnu egrep", or at least you are using the version of egrep inside the gnu folder.

It would be kind of you, if you would explain the functionality of "-B" option. I wasnt able to ascertain..

Thanks,
Srini
Last edited by srinivasan_85; 04-27-2007 at 08:54 AM.. Reason: Typographical mistakes
# 3  
Old 04-27-2007
It's not randomly, it's by design, from "man grep"
Quote:
-B NUM, --before-context=NUM
Print NUM lines of leading context before matching lines. Places a line containing -- between contiguous
groups of matches.
, so it's being used kinda as separator.
# 4  
Old 04-27-2007
Yea i'm using a GNU grep for this... "A" fetches lines below what you are looking for and "B" grabs lines above. I just created a perl script to strip them out before it writes to a new file. I'm terrible with using sed, awk, nawk etc.... so that was quickest fix for me.
 
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