Command for extracting lines before and after a particular searched string pattern.

grail · 07-22-2013, 11:14 AM

Well as far as I can see I think the follow solutions work. I have tested for multiple findings but not for overlapping:

Awk:

Code:

#!/usr/bin/awk -f

$0 ~ search{
	while(++j <= i)
		print save[j]
	
	j=0
	x=1
}

x{
	if(x++ <= BandA+1)
		print
	else{
		x=0
		print "---------------------"
	}
}

{
	if(i<BandA)
		save[++i]=$0
	else{
		for(k=2;k<=BandA;k++)
			save[k-1]=save[k]
		
		save[BandA]=$0
	}
}

Usage:

Code:

./script.awk -vsearch="Audi" -vBandA=10 file

Ruby:

Code:

#!/usr/bin/env ruby

BEGIN{
	size = ARGV[0].to_i
	search = ARGV[1]
	fname = ARGV[2]

	save = Array.new(size)
	next_10 = false
	cnt = 1
}

File.open(fname,'r'){
	|file|

	while file.gets

		if next_10
			puts $_
			if (cnt += 1) > size
				next_10 = false
				cnt = 1
				puts '---------------'
			end
		end

		if $_.match(search)
			puts save.join + $_
			next_10 = true
		end

		save = save.drop(1) if save.length == size
		save<<$_

	end

}

Usage:

Code:

./script.rb 10 Audi file

Neither code has too much error checking so I will leave that to the OP.
Also the dashes (-----) are just to see where a record was ending

Satyaveer Arya · 07-23-2013, 02:23 AM

Hi grail,

Thanks for the helpful script but when I run the script it give an error:

Quote:

awk: syntax error near line 3
awk: bailing out near line 3

Please advice.

Satyaveer Arya · 07-23-2013, 02:29 AM

Quote:

I read your first post VERY carefully, three times.
Is there some hidden meaning?
Maybe I am just not intelligent enough to understand your needs.
I apologize for wasting your time.

I know about the grep command daniel. But the thing is -C switch which you mentioned in your one of the posts do not support on my server. Also we're not authorized to upgrade the package to latest version.
That's why I'm here to get some help. And I'm not that much proficient in shell scripting, that's why I'm seeking some help from you guys.
And nothing is hidden.
I know you're intelligent buddy...

And no need to apologize buddy..

It's ok!

druuna · 07-23-2013, 02:37 AM

Quote:

Originally Posted by Satyaveer Arya

Hi grail,

Thanks for the helpful script but when I run the script it give an error:

Quote:

awk: syntax error near line 3
awk: bailing out near line 3

Please advice.

I just tried grails awk script and it works nicely without throwing any errors.

- Did you copy paste it correctly (as a plain text file)?
- Which awk / awk version are you using (awk --version)

Satyaveer Arya · 07-23-2013, 02:40 AM

Hi Schniedz,

I used your mentioned script also:

Quote:

linenum=`grep -n <HandBagCnt>END MessageForwarder.log.2013-07-03 | awk -F : '{print $1}'`
lo=`expr $linenum - 10`; hi=`expr $linenum + 10`
sed -n "$lo","$hi"p MessageForwarder.log.2013-07-03

Here I'm searching for <HandBagCnt>END string in MessageForwarder.log.2013-07-03 file. And MessageForwarder.log.2013-07-03 log file is of 7.8GB.

I just tried to run this above script like this:

Code:

# ./script

And it gave me this error:

Quote:

./script: HandBagCnt: cannot open
awk: syntax error near line 1
awk: bailing out near line 1
sed: illegal option -- 1

Please advise.

Firerat · 07-23-2013, 02:55 AM

Quote:

Originally Posted by Satyaveer Arya

Hi Schniedz,

I used your mentioned script also:

Here I'm searching for <HandBagCnt>END string in MessageForwarder.log.2013-07-03 file. And MessageForwarder.log.2013-07-03 log file is of 7.8GB.

I just tried to run this above script like this:

Code:

# ./script

And it gave me this error:

Please advise.

Code:

linenum=`grep -n "<HandBagCnt>END" MessageForwarder.log.2013-07-03 | awk -F : '{print $1}'`
lo=`expr $linenum - 10`; hi=`expr $linenum + 10`
sed -n "$lo","$hi"p MessageForwarder.log.2013-07-03

you need to use quotes, < and > are 'special' to the shell
It is trying to use file HandBagCnt as input and send output to the file END

http://www.tldp.org/LDP/abs/html/io-redirection.html

Which is why you get the error
>> ./script: HandBagCnt: cannot open

Satyaveer Arya · 07-23-2013, 03:25 AM

Hi druuna,

Quote:

- Did you copy paste it correctly (as a plain text file)?
- Which awk / awk version are you using (awk --version)

Yes I used the same script as mentioned by him.
And I used many methods which I know so far to check the version of awk, but none of them worked.
Can you please tell me how to check the version of awk on Solaris 10 ?

druuna · 07-23-2013, 03:36 AM

Quote:

Originally Posted by Satyaveer Arya

And I used many methods which I know so far to check the version of awk, but none of them worked.
Can you please tell me how to check the version of awk on Solaris 10 ?

This is the first time you mention using Solaris, which is rather important information.

Out of the box Solaris doesn't use GNU Awk. There is an alternative awk present you should use: /usr/xpg4/bin/awk

Try changing the following in grails code:

Code:

#!/usr/bin/awk -f

# change the above line to

#!/usr/xpg4/bin/awk -f

Can I correctly assume you tried running awk --version to get the awk information?

linosaurusroot · 07-23-2013, 04:40 AM

Quote:

Originally Posted by Satyaveer Arya

Hi grail,

Thanks for the helpful script but when I run the script it give an error:
awk: syntax error near line 3
awk: bailing out near line 3

Meaningful error messages is the main reason on SunOS for using nawk rather than awk.