Question

I have a input file with the following example data.

kernel_version hostname

2.6.32-220.el6.x86_64 www01.dc1.domain.com
2.6.32-220.el6.x86_64 www02.dc1.domain.com
2.6.32-220.el6.x86_64 exc01.dc1.domain.com
2.6.32-220.el6.x86_64 exc02.dc1.domain.com
2.6.32-120.el6.x86_64 www03.dc2.domain.com
2.6.32-120.el6.x86_64 www04.dc2.domain.com
2.6.32-120.el6.x86_64 exc03.dc2.domain.com
2.6.32-120.el6.x86_64 exc04.dc2.domain.com
2.6.32-100.el6.x86_64 www05.dc3.domain.com
2.6.32-100.el6.x86_64 www06.dc3.domain.com
2.6.32-100.el6.x86_64 exc05.dc3.domain.com
2.6.32-100.el6.x86_64 exc06.dc3.domain.com
2.6.32-220.el6.x86_64 www07.dc4.domain.com
2.6.32-220.el6.x86_64 www08.dc4.domain.com
2.6.32-220.el6.x86_64 exc07.dc4.domain.com
2.6.32-220.el6.x86_64 exc08.dc4.domain.com

I’d like to output the unique kernel version, and which dcs are running which.

For example;

2.6.32-220.el6.x86_64 dc1, dc4
2.6.32-120.el6.x86_64 dc2
2.6.32-100.el6.x86_64 dc3

What is the best method to achieve this?

Answer 1

I’d do something like this:

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

my %kernels;
open INPUT,"<inputfile";

while (<INPUT>)
{
    my ($version, $hostname) = split(/\s+/,$_);
    if ($kernels{$version}) { $kernels{$version} .= ", $hostname" }
    else { $kernels{$version} = $hostname }
}
close INPUT;    

# Print the summary
foreach my $kernel (keys(%kernels)) {   print "$kernel\t$kernels{$kernel}\n"; }

Warning: I did not test this script. I am not responsible for any syntax errors, race conditions, or velociraptor attacks that may be caused by this code.. but it should get you started

Edit: I have now tested it. One syntactical error that has been rectified, and no major velociraptor attacks.