script

[Satish Y]

Hi All,

I am writing a script that finds error messages from logs. I am finding by greping error msg number. The thing I am looking for is I want to grep 2,3 extra lines(following line containing my pattern). Can anybody tell me how to do that.

Thanks in advance.

Note: I don't know perl. I want it without using perl.

Cheers...
Satish.

[Sridhar Bhaskarla]

Satish,

Then you may want to use sed. Let's say your Error No is defined as $ERR and your pattern is $PATTERN, then use sed like this

sed -n '/'$ERR'/,/'$PATTERN'/p' your_log_file

This may not exactly give what you want. You can make some modifications to the above command and achive whatever you want.

-Sri

[Satish Y]

Hi Sridhar,

My error number and pattern r not different they r same, means i am using error number as my pattern.

Regards,
Satish.

[Volker Borowski · Accepted solution]

Just a try :

# cat trick.awk

BEGIN { pri = 0 }
{
if ( match($0, PAT ) > 0 )
pri = 3
if ( pri > 0 )
{
print
pri = pri - 1
}
}

# cat test.txt

dkjh dfkgj hfgkdjh gdkj ghdkgjdf
df gkjhfgkfj kfjh dkfgj hdkgh fdkg
fdl gkjfldgkjdflgkjdfgl TARGET
1
2
3
4

# awk -v PAT=TARGET -f trick.awk test.txt

fdl gkjfldgkjdflgkjdfgl TARGET
1
2


may be you need to put the calling commandline in a script to pass PAT=$1 as a parameter.
Change "pri=3" if you want more lines after the hit.

Volker

[John Waller]

Give Volker the 10 points , it is only small and it works a treat, it will help me out a loads with a similar problem I have.

[harry d brown jr]

You could use the GNU grep, found here:

http://www.gnu.org/software/grep/grep.html

With GNU grep you get a lot more options. The "-A 1" with the "-B 1" options will display the line before the matching line, the matching line, and then the trailing line.

[Sridhar Bhaskarla]

Satish,

It would be nice if you can cat few lines of your log file and tell us what you want to extract. Check up the following script.

#!/usr/bin/ksh

ERR=$1
LEN=$2

/usr/bin/sed -n '/'$ERR'/,$p' your_log |sed -n '1,'$LEN'p'

Now you can pass two arguments to this script
Arg1=Your Error Number and LEN=Number of lines you want to print.

Let me know if this helped you.

-Sri

[Satish Y]

Thanks for all your responses,

Thanks Volker for a nice script...

Excellent Sridhar, it worked well...
I also want to grep 2 lines before the pattern, is it possible?...
One more thing I didn't understand what $p does in ur sed statement. Can u explain?.

Waiting for reply....

Cheers...
Sat.

[Sridhar Bhaskarla]

Satish,

Yes.. there is a straight method but I don't remember it now. I can tell you a work around.

Try this way.

#!/usr/bin/ksh

ERR=$1
PRE=`echo "$2 + 1"|bc`
POST=$3

/usr/bin/sed -n '1,/$ERR/p' your_log |tail -$PRE > result

/usr/bin/sed -n '/'$ERR'/,$p' your_log |sed -n '2,'$POST'p' >> result

p is the print macro in sed.

I do not have a system in front of me. So I am not sure if it works.. But you can adjust and make it to work.

-Sri

[Volker Borowski]

OK,
another try. This is difficult, because you need to store the lines before your hit, because you do not really know, if you'll need them.
... and if there is a double hit, you may not reprint an already printed line.
If you want do seperate the hits, you might insert
print "-------"
before you print DELTA2.
For more leading lines, add more DELTAx, but to handle the double hits correctly, the number of printed lines after the hit (pri=3) needs to be greater or equal the number of DELTAx lines.

Hey these puzzles are fun :-)

here we go:
#########################
BTW: Does anyone know, why this textbox is eliminating my leading blanks ?

Volker

# cat trick.awk

BEGIN { pri = 0 }
{
if ( match($0, PAT ) > 0 )
{
if ( pri == 0 )
{
print DELTA2
print DELTA1
}
pri = 3
}
if ( pri > 0 )
{
print
pri = pri - 1
}
DELTA2 = DELTA1
DELTA1 = $0
}

# cat test.txt

no printline
second before target 1 (easy)
first before target 1 (easy)
first:first TARGET garbage
1
2
3
no printline
no printline
no printline
second before target 2 (easy)
first before target 2 (easy)
second:second TARGET garbage
1
mean:mean TARGET garbage
2
3
no printline
no printline
no printline
no printline

# awk -v PAT=TARGET -f trick.awk test.txt

second before target 1 (easy)
first before target 1 (easy)
first:first TARGET garbage
1
2
second before target 2 (easy)
first before target 2 (easy)
second:second TARGET garbage
1
mean:mean TARGET garbage
2
3

#

[Satish Y]

Thanks all for your great responses....

Cheers...
Satish.

[Bill McNAMARA_1]

well done Volker, I was just about to post for the same thing..
nice script!

Later,
Bill