use 5.020; use Fcntl; use strict; use warnings; my $file_name = 'C:\Windows\notepad.exe'; my $size = -s $file_name; my ($data_open, $data_sysopen); { open my $fh1, '<', $file_name; binmode $fh1; local $/; $data_open = <$fh1>; close $fh1; } { sysopen my $fh2, $file_name, O_RDONLY; binmode $fh2; read ($fh2, $data_sysopen, $size); } say "Groesse: ", $size; say "Laenge gleich: ", length($data_open), ' | ' , length($data_sysopen); say "Daten ", $data_open ne $data_sysopen ? 'ungleich' : 'gleich';