Comparing two text files

[Lancy]

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[GrandFather]

It may be urgent for you, but that doesn't make it urgent for us. However, if you used a sensible title, took the time to format your node correctly, and provided a small self contained script showing the issue you are having you'd generally get pretty prompt response.

Laziness is much better served by taking the time to do a good job the first time rather than rehashing a "quick and dirty" version over and over until you either run out of time or stamina or it ends up working just well enough to solve the immediate problem.

[Anonymous Monk]

s/// is the substitution operator, generally not used for comparison, you want m// the match operator

#!/usr/bin/perl --
#~ 2011-09-07-00:31:00 by Anonymous Monk
#~ perltidy -csc -otr -opr -ce -nibc -i=4
use strict;
use warnings;
use autodie;    # dies if open/close... fail

Main(@ARGV);
exit(0);

sub Main {
    if ( @_ == 3 ) {
        NotDemoMeaningfulName(@_);
    } else {
        Demo();
        print Usage();
    }
} ## end sub Main

sub NotDemoMeaningfulName {
    my ( $inputOne, $inputTwo, $outputFile ) = @_;
    open my ($inOne), '<', $inputOne;
    open my ($inTwo), '<', $inputTwo;
    open my ($outFh), '>', $outputFile;
    while ( not eof $inOne ) {
        my $onel = <$inOne>;
        my $twol = <$inTwo>;
        for ( $onel, $twol ) {
            chomp;
            $_ = $1 if /,\s*([^,]+)$/;
        }
        print $outFh "{$onel}{$twol}\n";
    } ## end while ( not eof $inOne )
    close $inOne;
    close $inTwo;
    close $outFh;
} ## end sub NotDemoMeaningfulName

sub Usage {
    <<"__USAGE__";


$0    
$0    dataFile1    dataFile2    outputFile
    
    perl ${\__FILE__}    
    perl ${\__FILE__}        dataFile1    dataFile2    outputFile


__USAGE__
} ## end sub Usage

sub Demo {
    my ( $Input, $Input2, $WantedOutput ) = DemoData();
    NotDemoMeaningfulName( $Input, $Input2, \my $Output );
    print $Output, "\n\n";
    require Test::More;
    Test::More::is( $Output, $WantedOutput,
        ' NotDemoMeaningfulName Works Aas Designed' );
    Test::More::done_testing();
} ## end sub Demo

sub DemoData {
    my $One = <<'__One__';
Optometrists and Opticians (simple) Regulations, Cap. 500A, RG 2
__One__

    my $Two = <<'__Two__';
OPTOMETRISTS AND OPTICIANS (SIMPLE) REGULATIONS, Cap. 500A, Regulation
+ 2
__Two__

    my $Three = <<'__Two__';
{RG 2}{Regulation 2}
__Two__

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

$ prove  pm.924549.pl
pm.924549.pl .. ok
All tests successful.
Files=1, Tests=1,  1 wallclock secs ( 0.12 usr +  0.06 sys =  0.19 CPU
+)
Result: PASS

$ perl pm.924549.pl
{RG 2}{Regulation 2}


ok 1 -  NotDemoMeaningfulName Works Aas Designed
1..1


pm.924549.pl
pm.924549.pl    dataFile1    dataFile2    outputFile

    perl pm.924549.pl
    perl pm.924549.pl        dataFile1    dataFile2    outputFile

Your title is not very effective ( see How do I compose an effective node title?, Markup in the Monastery ) and remember, "Your 'urgent need' is not our emergency."