use strict;

open (FOO, "test") ||
    die "ERROR Unable to open test: $!\n";

my $first = <FOO>;
my $last = $first;
while (<FOO>) {$last = $_}
close FOO;
print "$first\n$last\n";
[download]

There is a lot of copying but no more than one line is stored in memory.
update - added my $last = $first; in case file only has one line.

--

flounder