use Path::Class;

my $file = './hello.txt';
my $path = Path::Class::File->new($file)->absolute;

print "the file ", $path->basename",
    "is in the ", $path->dir, "directory\n";

# or if dealing with file specifications of a different platform...
$file = "c:\\Documents and Settings\\you\\..\\me\\hello.txt";
$path = Path::Class::File->new_foreign('Win32', $file)->absolute;