[Perl-beginners] removing duplicate lines across files.

UNTESTED:

#!/usr/bin/perl
use warnings;
use strict;

my $file = 'file1';

open my $fh, '<', $file or die "Cannot open '$file' $!";

my %lines;
@lines{ <$fh> } = ();

close $fh;

{ local ( $^I, @ARGV ) = qw/ .bak file2 file3 file4 file5 /;

while ( <> ) {
next if exists $lines{ $_ };
print;
}
}

__END__



John

Hi Gurus,



Sorry I did not give detailed description of the problem, Here it goes





I have a array of file names (file1, file2, file3, file4).



Each the duplicates should be removed in the below fashion



The lines in file1 should be removed from file2,fiile3,file4,If they
exists.

The lines in file2 should be removed from file3,file4 if They exists,

The lines in file3 should be removed from file4 if they exists.



Is there any way apart from forloop



Thanks in Advance

Siva









-----Original Message-----
From: John W. Krahn
Sent: Thursday, January 03, 2008 4:04 PM
To: Perl Beginners
Subject: Re: removing duplicate lines across files.



Siva Prasad wrote:

>


Hello,


>

>


UNTESTED:



#!/usr/bin/perl

use warnings;

use strict;



my $file = 'file1';



open my $fh, '<', $file or die "Cannot open '$file' $!";



my %lines;

@lines{ <$fh> } = ();



close $fh;



{ local ( $^I, @ARGV ) = qw/ .bak file2 file3 file4 file5 /;



while ( <> ) {

next if exists $lines{ $_ };

print;

}

}



__END__







John

You have been asked already not to makes posts in blue lettering. Please
have the courtesy to post in a fashion appropriate for the list.

read the faq article

perldoc -q duplicate elements

which describes how to do this with an array of data. Hopefully you can
make the step to doing the same thing with disk files.

HTH,

Rob