removing certain paragraphs for matching patterns

kaushys · #1 (**permalink**) 07-18-2008

Hi,
I have a log file which might have certain paragraphs.

Switch not possible Error code 1234
Process number 678

Log not available Error code 567
Process number 874
.....
......
......

Now I create an exception file like this.

cat text.exp
Error code 1234
Process number 874

What I want is to read my original file but exclude any paragraphs that might contact the keywords written in the exception file. How can I do that?

yunccll · #2 (**permalink**) 07-18-2008

Code:

$ cat file1
Switch not possible Error code 1234
Process number 678
 
Log not available Error code 567
Process number 874
 
Log not available Error code 333
Process number 34
 
Log not available Error code 33334234
Process number 012
 
Log not available Error code 333 hello
Process number 012
 
Log not available Error code 567
Process number 8743434
 
Log not available Error code 567
Process number 874 ok

Code:

$ cat text.exp 
Error code 1234
Process number 874
Error code 333

Code:

$ ./script.sh 
Log not available Error code 33334234
Process number 012
 
Log not available Error code 567
Process number 8743434

Code:

$ cat script.sh 
#!/bin/bash
awk '
  BEGIN{
        RS=""; ORS="\n\n"
  }
  NR == FNR{
        split($0, arr, "\n");
  }
  NR != FNR{
        str = $0 "\n"
        for(i=1; i <= length(arr); i++){
          regx = arr[i] "[[:space:]?|\n]"
          if(str ~ regx) break;
        }
        if(i > length(arr)) print $0
  }
' text.exp file1

hope to help u!

.Aaron

kaushys · #3 (**permalink**) 07-19-2008

I am not sure how it works but looks like this could help me. Thank you for such a short turnaround. I will check the awk script and see how it works.

Just as a doubt can't I use a while read do loop and do the same thing. Something like this...

cat tem.exp | while read exception
do
cat file | grep -iv $exception
done

I know the above code is not right. But thats just a basic idea. I dont know how to remove a para in the first place. And then I need to do it in a loop so that I parse each line in the exception file.

drl · #4 (**permalink**) 07-19-2008

Hi.

This is a long solution, but modular for generality. It consists primarily of 2 perl scripts. The first reads paragraphs and creates single lines of them, using a character for the newline (I used "%"). The second perl script does the opposite, takes the long "%"-embedded lines, and creates separate lines.

With those two on the outside, we can manipulate the file as we wish with line-oriented *nix tools. In this demonstration a grep is used to eliminate paragraphs (long lines) matching the phrases you wish.

Here are the perl scripts:

Code:

#!/usr/bin/perl

# @(#) p1       Demonstrate paragraphs into lines, substitution for newline.

use warnings;
use strict;

my($debug);
$debug = 0;
$debug = 1;

my($FAKE_RS) = "%";

# read paragraphs
$/ = "\n\n";

while ( <> ) {
        s/\n/$FAKE_RS/msg;
        print "$_\n";
}

exit(0);

and:

Code:

#!/usr/bin/perl

# @(#) p2       Demonstrate read lines, substituting newline.

use warnings;
use strict;

my($debug);
$debug = 0;
$debug = 1;

my($FAKE_RS) = "%";

while ( <> ) {
        s/$FAKE_RS$FAKE_RS/\n/msg;
        s/$FAKE_RS/\n/msg;
        print "$_";
}

exit(0);

These can be driven by a shell script:

Code:

#!/bin/bash -

# @(#) s1       Demonstrate pipeline for paragraph matching.

echo
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version =o $(_eat $0 $1)
set -o nounset
echo

FILE1=data1
FILE2=data2

echo
echo " Data file $FILE1:"
cat $FILE1

echo
echo " Data file $FILE2:"
cat $FILE2

echo
echo " Results:"
./p1 $FILE1 |
tee t1 |
grep -v -f $FILE2 |
tee t2 |
./p2

exit 0

Producing:

Code:

% ./s1

(Versions displayed with local utility "version")
Linux 2.6.11-x1
GNU bash 2.05b.0


 Data file data1:
Switch not possible Error code 1234
Process number 678

Log not available Error code 567
Process number 874

Log not available Error code 333
Process number 34

Log not available Error code 33334234
Process number 012

Log not available Error code 333 hello
Process number 012

Log not available Error code 567
Process number 8743434

Log not available Error code 567
Process number 874 ok

Log not available Error code 999
Process number 777 missing

 Data file data2:
Error code 1234
Error code 333
Process number 874%

 Results:
Log not available Error code 567
Process number 8743434

Log not available Error code 567
Process number 874 ok

Log not available Error code 999
Process number 777 missing

The patterns to be excluded could contain a "%" to force exclusion of patterns ending at the point corresponding to a newline, as with pattern 3. If the character "%" occurs in either data file, then changes would need to be made to the perl scripts and the pattern data file. However, the manipulation is generally unaware that it is operating on paragraphs -- it sees everything as just a line, a long line to be sure, but just a line. This places the complexity outside the scope of the real operation you wish to perform.

The intermediate files t1 and t2 may be viewed to see in more detail how the process works. The tee commands may be removed when desired -- just delete the lines, that's why they are on separate lines in the pipeline.

The paragraphs must be separated by empty lines, no spaces, TABs, etc. are allowed, only a newline.

See man pages for details ... cheers, drl

summer_cherry · #5 (**permalink**) 07-21-2008

awk:

Code:

nawk '{
if (NR==FNR){arr[$NF]++}
else{
if (FNR%3==1)
{
        if($NF in arr){flag=1}
        else{t=$0}
}
else if(FNR%3==2){
	if($NF in arr || flag==1){flag=0;next}
        else{print t;print $0}
}
else
        next
}
}' text.exp file

perl:

Code:

open FH,"<text.exp";
while(<FH>){
	@arr=split(" ",$_);
	%hash=(%hash,$arr[$#arr],$.);
}
close(FH);
open FH,"<file";
while(<FH>){
	@temp=split(" ",$_);
	$t=$temp[$#temp];
	$line=$_ if (!exists($hash{$t}) && $.%3==1);
	if(!exists($hash{$t}) && $.%3==2){
		if(length($line)>0){
			push(@res,$line);
			push(@res,$_);
		}
	}
	if($,%3==0){
		next;
	}
}
foreach (@res){
print;
}
close(FH);

kaushys · #6 (**permalink**) 07-22-2008

Thank you so much. This was really easy with so many options.

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