Re: removing a column

[johngg]

It is a good idea to check for the success of your opens and closes and to use the three argument form for open with lexical filehandles. You should also use single quotes if you don't need interpolation.

my $hostfile = '/tmp/jn/hosts';
open my $hostFH, '<', $hostfile
   or die "open: < $hostfile: $!\n";

You need to take care when sorting IPs as a simple lexical sort will give odd results.

$ perl -le '
> @IPs = qw{ 22.32.87.12 56.67.38.61 101.12.34.54 };
> print for sort @IPs;'
101.12.34.54
22.32.87.12
56.67.38.61
$

I use sprintf here to form each quad into a fixed width string with leading zeros, making a 12-digit string that can be sorted lexically.

use strict;
use warnings;

my %seen;
my @sortedUniques =
   map  { ( split m{\s+}, $_->[ 0 ] )[ 0 ] }
   sort { $a->[ 1 ] cmp $b->[ 1 ] }
   grep { ! $seen{ $_->[ 1 ] } ++ }
   map  {
            m{^(\d+)\.(\d+)\.(\d+)\.(\d+)\t}
            ? [ $_, sprintf q{%03d%03d%03d%03d}, $1, $2, $3, $4 ]
            : ()
        }
   <DATA>;

print qq{$_\n} for @sortedUniques;

__END__
# hosts file

10.31.17.65    fw2
192.168.1.78    hosta
192.168.1.21    hostb
10.31.17.65    fw2dup
10.23.212.6    hostc
192.168.100.254    fw1
192.168.1.21    hostbdup

The output.

10.23.212.6
10.31.17.65
192.168.1.21
192.168.1.78
192.168.100.254

I hope this is helpful.

[poolpi]

Or at least use autodie ;)


use autodie qw(open close); # open/close succeed or die


hth,
PooLpi

[jn64024]

All, Thank you for the information....I have taken all in consideration to finish off what I have.

I love this language as it just shows above how many different ways the same thing can be completed along with all the considerations in error checking.

Again thank you all very much!