[SOLVED] grep showing all matches?

kadalurpenguin · 05-22-2012, 12:28 PM

Hi All,
I have a file called ip-mac.txt in which IP and MAC addresses are stored.

Code:

$cat ip-mac.txt
192.168.0.1 00:00:00:00:00:01 
192.168.0.2 00:00:00:00:00:02
192.168.0.3 00:00:00:00:00:03
192.168.0.4 00:00:00:00:00:04
192.168.0.5 00:00:00:00:00:05
192.168.0.6 00:00:00:00:00:06
192.168.0.7 00:00:00:00:00:07
192.168.0.8 00:00:00:00:00:08
192.168.0.9 00:00:00:00:00:09
192.168.0.10 00:00:00:00:00:10
192.168.0.11 00:00:00:00:00:11
192.168.0.12 00:00:00:00:00:12
192.168.0.13 00:00:00:00:00:13
192.168.0.14 00:00:00:00:00:14
192.168.0.15 00:00:00:00:00:15
192.168.0.16 00:00:00:00:00:16
192.168.0.20 00:00:00:00:00:20

When I search for "192.168.0.1", it is showing all of the matches even the command is without case insensitive.

Code:

$grep "192.168.0.1" ip-mac.txt
192.168.0.1 00:00:00:00:00:01 
192.168.0.10 00:00:00:00:00:10
192.168.0.11 00:00:00:00:00:11
192.168.0.12 00:00:00:00:00:12
192.168.0.13 00:00:00:00:00:13
192.168.0.14 00:00:00:00:00:14
192.168.0.15 00:00:00:00:00:15
192.168.0.16 00:00:00:00:00:16

$grep "192.168.0.2" ip-mac.txt
192.168.0.2 00:00:00:00:00:02
192.168.0.20 00:00:00:00:00:20

Tried also without the quote and getting the same

Code:

$grep 192.168.0.2 ip-mac.txt
192.168.0.2 00:00:00:00:00:02
192.168.0.20 00:00:00:00:00:20

I don't know why and I need the result to be with only that IP for which I am doing grep. So please help me in how to get the result with only that particular IP and ignore all other matches.
Thanks in advance and your kind help would really be appreciated.

em31amit · 05-22-2012, 12:45 PM

you can do something like this.

Code:

cat ip-mac.txt
192.168.0.1 00:00:00:00:00:01 
192.168.0.2 00:00:00:00:00:02
192.168.0.3 00:00:00:00:00:03
192.168.0.4 00:00:00:00:00:04
192.168.0.5 00:00:00:00:00:05
192.168.0.6 00:00:00:00:00:06
192.168.0.7 00:00:00:00:00:07
192.168.0.8 00:00:00:00:00:08
192.168.0.9 00:00:00:00:00:09
192.168.0.10 00:00:00:00:00:10
192.168.0.11 00:00:00:00:00:11
192.168.0.12 00:00:00:00:00:12
192.168.0.13 00:00:00:00:00:13
192.168.0.14 00:00:00:00:00:14
192.168.0.15 00:00:00:00:00:15
192.168.0.16 00:00:00:00:00:16
192.168.0.20 00:00:00:00:00:20



$ grep '192.168.0.2 ' ip-mac.txt 
192.168.0.2 00:00:00:00:00:02

you need to use single quote (') and use a blank space after last digit for eg. here i am denoting blank space with "B" so you need to use
grep '192.168.0.1B' filename

actual command

Code:

grep 'IP ' filename

that's it. and working on my machine.

kadalurpenguin · 05-22-2012, 12:54 PM

Thanks a ton em31amit

Quote:

grep 'IP ' filename

that's it. and working on my machine.

Super it is working great.

colucix · 05-22-2012, 01:55 PM

Or simply use the -w option:

Code:

grep -w 192.168.0.1 ip-mac.txt

Tinkster · 05-22-2012, 01:58 PM

The 'problem' you were facing, btw, is that you assume RegEx to
be word-centric. They're not. They're strictly character based,
and the solution above will fail if the separator is a TAB, for
example. You could use (e)grep, and either go with the -w option,
or you could use egrep with the a regex that makes use of word
boundaries, or grep with a regex that tackles both kinds of
in-line whitespace:

Code:

(e)grep -w 192.168.0.1
egrep  "192.168.0.1\b"
grep  "192.168.0.1[[:space:]]"

Cheers,
Tink

kadalurpenguin · 05-22-2012, 09:05 PM

Quote:

grep -w 192.168.0.1 ip-mac.txt
(e)grep -w 192.168.0.1
egrep "192.168.0.1\b"
grep "192.168.0.1[[:space:]]"

Super, all of the above codes are working fine.
Thank you all for giving more information about regex.