$ftp->put ( $input_file, $new_file_name ) or die "did not upload $input_file to $new_file_name: " . $ftp->message;

##</code><code>##

use File::Basename wq(basename);
my $new_file_name = basename($input_file);
die "no such file: $input_file" unless -s $input_file;

$ftp->put ( $input_file, $new_file_name ) or die "did not upload $input_file to $new_file_name: " . $ftp->message;