use File::Spec;
use Win32;

my $absolute_path = Win32::GetFullPathName(File::Spec->join("C:\\Perl\\bin", "..\\lib\\File\\Spec.pm"));

##</code><code>##

use File::Spec;
use Cwd;
my $absolute_path = Cwd::abs_path(File::Spec->join("/usr/bin", "../lib"));