my $stuff = 'file.txt';
open(F, "$stuff") || die "Can not open file: $!\n";
my @records = (<F>);
print "@records\n";
s/lastlineofdata//;  #This is the part I am struggling with
close(F);

##</code><code>##

use strict;
use warnings;

use IO::File;

my $filename = 'file.txt';

my $in_fh = IO::File->new($filename)
    || die "Can not open '$filename' for reading: $!\n";
my @records = <$in_fh>;
$in_fh->close;

print "@records\n";
pop @records;

my $out_fh = IO::File->new(">$filename")
    || die "Cannot open '$filename' for writing: $!\n";

print $out_fh, @records;

$out_fh->close;

##</code><code>##

perl -pi -e 'last if eof()' file.txt