$ ls -l xxxx
-rw-r--r--   1 johngg   users        639 Jun 19 23:26 xxxx
$ perl -le '
> open $in, q{<}, q{xxxx} or die $!;
> seek $in, 1000, 0 == tell $in or die q{bad seek};
> print tell $in;
> 10 == read $in, $buf, 10 or die q{bad read};
> print tell $in;
> print $buf;'
1000
bad read at -e line 5.
$