If I understand you, what you are looking for is a combination of $^O and several CPAN modules. Once you have the operating system name in hand, you use the functions provided by packages in the $^O::Sysinfo or Win32::SystemInfo (in the case of Windows) name space to extract the information you want.

Example:

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

use Linux::SysInfo;
use Win32::SystemInfo;

my $this_system = $^O;

if ($this_system eq 'MSwin32') {
    my %windata;
    Win32::SystemInfo::MemoryStatus(%windata);
    ####
    #  process the results
    ####
} elsif ($this_system eq 'Linux') {
    my %linuxdata;
    %linuxdata = Linux::SysInfo::sysinfo() or die "Linux::SysInfo::sys
+info() failed";
    #####
    # process the results
    #####
} else {
     die "Undefined OS -- $this_system";
}

exit(0);
[download]