{
   local $/=\"1024";
   open FILE, 'c:\space\sp.txt' or die $!;
   $_=<FILE>; #<IT WILL READ ONLY 1KB>
}
# now $/ is back to its original value

# another way (note that quotes are not needed):

open FILE, $name or die $!;
$_ = do { local $/ = \1024; <FILE> };