Linux::Distribution - Perl extension to detect on which Linux distribution we are running.

  use Linux::Distribution qw(distribution_name distribution_version);

  if(my $distro = distribution_name) {
        my $version = distribution_version();
  	print "you are running $distro, version $version\n";
  } else {
  	print "distribution unknown\n";
  }

  Or else do it OO:

  use Linux::Distribution qw(distribution_name distribution_version);

  my $linux = Linux::Distribution->new;
  if(my $distro = $linux->distribution_name()) {
        my $version = $linux->distribution_version();
        print "you are running $distro, version $version\n";
  } else {
        print "distribution unknown\n";
  }

package Linux::Distribution;

use 5.006000;
use strict;
use warnings;

require Exporter;

our @ISA = qw(Exporter);

our @EXPORT_OK = qw( distribution_name distribution_version );

our $VERSION = '0.20';

our $release_files_directory='/etc';
our $standard_release_file = 'lsb-release';

our %release_files = (
    'gentoo-release'        => 'gentoo',
    'fedora-release'        => 'fedora',
    'turbolinux-release'    => 'turbolinux',
    'mandrake-release'      => 'mandrake',
    'mandrakelinux-release' => 'mandrakelinux',
    'debian_version'        => 'debian',
    'debian_release'        => 'debian',
    'SuSE-release'          => 'suse',
    'knoppix-version'       => 'knoppix',
    'yellowdog-release'     => 'yellowdog',
    'slackware-version'     => 'slackware',
    'slackware-release'     => 'slackware',
    'redflag-release'       => 'redflag',
    'redhat-release'        => 'redhat',
    'redhat_version'        => 'redhat',
    'conectiva-release'     => 'conectiva',
    'immunix-release'       => 'immunix',
    'tinysofa-release'      => 'tinysofa',
    'trustix-release'       => 'trustix',
    'adamantix_version'     => 'adamantix',
    'yoper-release'         => 'yoper',
    'arch-release'          => 'arch',
    'libranet_version'      => 'libranet',
    'va-release'            => 'va-linux',
    'pardus-release'        => 'pardus',
);

our %version_match = (
    'gentoo'                => 'Gentoo Base System release (.*)',
    'debian'                => '(.+)',
    'suse'                  => 'VERSION = (.*)',
    'fedora'                => 'Fedora Core release (\d+) \(',
    'redflag'               => 'Red Flag (?:Desktop|Linux) (?:release |\()(.*?)(?: \(.+)?\)',
    'redhat'                => 'Red Hat Linux release (.*) \(',
    'slackware'             => '^Slackware (.+)$',
    'pardus'                => '^Pardus (.+)$',
    'centos'                => '^CentOS release (.+)(?:\s\(Final\))',
);


if ($^O ne 'linux') {
#	require Carp;
#	Carp::croak('you are trying to use a linux specific module on a different OS');
}

sub new {
    my %self = (
        'DISTRIB_ID'          => '',
        'DISTRIB_RELEASE'     => '',
        'DISTRIB_CODENAME'    => '',
        'DISTRIB_DESCRIPTION' => '',
        'release_file'        => '',
        'pattern'             => ''
    );
    
    return bless \%self;
}

sub distribution_name {
    my $self = shift || new();
    my $distro;
    if ($distro = $self->_get_lsb_info()){
        return $distro if ($distro);
    }

    foreach ('fedora-release') {
        if (-f "$release_files_directory/$_" && !-l "$release_files_directory/$_"){
            if (-f "$release_files_directory/$_" && !-l "$release_files_directory/$_"){
                $self->{'DISTRIB_ID'} = $release_files{$_};
                $self->{'release_file'} = $_;
                return $self->{'DISTRIB_ID'};
            }
        }
    }

    foreach (keys %release_files) {
        if (-f "$release_files_directory/$_" && !-l "$release_files_directory/$_"){
            if (-f "$release_files_directory/$_" && !-l "$release_files_directory/$_"){
                if ( $release_files{$_} eq 'redhat' ) {
                    $self->{'pattern'} = $version_match{'centos'};
                    $self->{'release_file'}='redhat-release';
                    if ( $self->_get_file_info() ) {
                        $self->{'DISTRIB_ID'} = 'centos';
                        $self->{'release_file'} = $_;
                        return $self->{'DISTRIB_ID'};
                    } else {
                        $self->{'pattern'}='';
                    }
                }
                $self->{'release_file'} = $_;
                $self->{'DISTRIB_ID'} = $release_files{$_};
                return $self->{'DISTRIB_ID'};
            }
        }
    }
    undef 
}

sub distribution_version {
    my $self = shift || new();
    my $release;
    return $release if ($release = $self->_get_lsb_info('DISTRIB_RELEASE'));
    if (! $self->{'DISTRIB_ID'}){
         $self->distribution_name() or die 'No version because no distro.';
    }
    $self->{'pattern'} = $version_match{$self->{'DISTRIB_ID'}};
    $release = $self->_get_file_info();
    $self->{'DISTRIB_RELEASE'} = $release;
    return $release;
}

sub _get_lsb_info {
    my $self = shift;
    my $field = shift || 'DISTRIB_ID';
    my $tmp = $self->{'release_file'};
    if ( -r "$release_files_directory/" . $standard_release_file ) {
        $self->{'release_file'} = $standard_release_file;
        $self->{'pattern'} = $field . '=(.+)';
        my $info = $self->_get_file_info();
        if ($info){
            $self->{$field} = $info;
            return $info
        }
    } 
    $self->{'release_file'} = $tmp;
    $self->{'pattern'} = '';
    undef;
}

sub _get_file_info {
    my $self = shift;
    open my $fh, '<', "$release_files_directory/" . $self->{'release_file'} or die 'Cannot open file: '.$release_files_directory.'/' . $self->{'release_file'};
    my $info = '';
    local $_;
    while (<$fh>){
        chomp $_;
        ($info) = $_ =~ m/$self->{'pattern'}/;
        return "\L$info" if $info;
    }
    undef;
}

1;
__END__