http://www.perlmonks.org?node_id=1005499


in reply to Re^6: How to print the lines immediately above and below a matching line?
in thread How to print the lines immediately above and below a matching line?

Well, that will never issue that warning :) anyway this is what I imagine you're after, you can add lots of print/warn debugging statements to figure out how it works 

#!/usr/bin/perl --
#~ 2012-11-25-06:19:07PDT by Anonymous Monk
#~ perltidy -olq  -csc -csci=10 -cscl="sub : BEGIN END" -otr -opr -ce 
+-nibc -i=4 -pt=0   "-nsak=*"
use strict;
use warnings;
use autodie;    # dies if open/close... fail

Main( @ARGV );
exit( 0 );

sub Main {
    if( @_ == 3 ) {
        NotDemoMeaningfulName( @_ );
    } else {
        Demo();
        print '#' x 33, "\n", Usage();
    }
}

sub NotDemoMeaningfulName {
    my( $inputFile, $outputFile, $dataFile ) = @_;
    my $DataRegex = MakeRegex( $dataFile );
    open my( $inFh ),  '<', $inputFile;
    open my( $outFh ), '>', $outputFile;

    my $this_line = "";
    my $do_next   = 0;
    while( <$inFh> ) {
        my $last_line = $this_line;
        $this_line = $_;

        if( $this_line =~ m{$DataRegex} ) {
            print $outFh $last_line unless $do_next;
            print $outFh $this_line;
            $do_next = 1;
        } else {
            print $outFh $this_line if $do_next;
            $last_line = "";
            $do_next   = 0;
        }
    }
    close $inFh;
    close $outFh;
} ## end sub NotDemoMeaningfulName

sub Usage {
    <<"__USAGE__";


$0    
$0    infile  outfile datafile
    
    perl ${\__FILE__}    
    perl ${\__FILE__}    infile  outfile datafile


__USAGE__
} ## end sub Usage

sub MakeRegex {
    my( $inputFile ) = @_;
    open my( $data ), '<', $inputFile;
    my @dForRex;
    while( <$data> ) {
        chomp;
        push @dForRex, quotemeta $_;
    }
    my $rex = join '|', @dForRex;
    qr{$rex};
} ## end sub MakeRegex

sub Demo {
    my( $Input, $WantedOutput, $Data ) = DemoData();
    NotDemoMeaningfulName( \$Input, \my $Output, \$Data );
    require Test::More;
    Test::More::is( $Output, $WantedOutput,
        ' NotDemoMeaningfulName Works Aas Designed' );
    Test::More::done_testing();
}

sub DemoData {

#~ http://perlmonks...
    my $One = <<'__One__';
0   yes I am
1a  Faking it :)
2b  with a 4386_7#8
3c  then a 4386_7#11
4   cause I go to 12
5a  and thirteen too
6b  shabba 4350_7#6
7c  shabba shooby dooby doo
8   ha cha cha cha
9   hi hi hi
__One__

#~ http://perlmonks...
    my $Two = <<'__Two__';
__Two__

#~ http://perlmonks...
    my $Three = <<'__Three__';
4386_7#8
4350_7#6
4414_1#6
__Three__

    return $One, $Two, $Three;
} ## end sub DemoData
__END__

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Re^8: How to print the lines immediately above and below a matching line?
by MB123 (Initiate) on Nov 25, 2012 at 18:41 UTC
    That's great, many thanks for your help!
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