grep help, please

[Diametric]

Hello,

I have a samba log file I'm trying to pull data from (/var/log/samba/log.combined). Specifically, I am trying to pull all lines from the file where a specific IP is mentioned

less log.combined | grep 10.1.4.* > file1

However, this particular log file actually has two lines per data instance. Example:

[2012/04/12 03:03:46, 3] nmbd/nmbd_incomingrequests.c:process_name_query_request(454)
process_name_query_request: Name query from 10.1.4.54 on subnet 10.1.0.115 for name WPAD<00>

So, my grep returns data from the third line, but I also need the first line to know when said IP attempted access. How do I pull this off?

Thanks!

[Lars Noodén]

Try this:

grep 10.1.4 log.combined > file1

Can you show a few sample lines from the log file?

[Diametric]

It's there, I just didn't wrap code filter around the instance.

[Lars Noodén]

There should be a way to use awk to grab a line with a pattern along with the preceding line.

[Diametric]

Thanks for your replies - I just don't know enough about awk to pull that off in a reasonable amount of time. Hell...I'm proud I was able to get that grep command to work!

[Vaphell]

grep -B2 ...
-Bn include n lines before matching line
-An include n lines after matching line

example

$ echo $'1\n2\n3\n4\n5'
1
2
3
4
5
$ echo $'1\n2\n3\n4\n5' | grep -A2 '3'
3
4
5
$ echo $'1\n2\n3\n4\n5' | grep -B2 '3'
1
2
3
$ echo $'1\n2\n3\n4\n5' | grep -B1 -A1 '3'
2
3
4

[Diametric]

grep -B2 ...
-Bn include n lines before matching line
-An include n lines after matching line

Perfect! Thank you so much, I have exactly what I was looking for.

Cheers.

[Lars Noodén]

grep -B2 ...
-Bn include n lines before matching line
-An include n lines after matching line

That's awesome!