#!/usr/bin/perl

my $file = "pg-write3";

{
    open my $fh, $file or die "open: $!";
    $line = <$fh>;
    $line = <$fh>;
    print "two reads:\t$.\n";
}
# $fh is closed here
print "closed file:\t$.\n";

{
    open my $fh, $file or die "open: $!";
    print "open again:\t$.\n";
    $line = <$fh>;
    print "one read:\t$.\n";
}
# $fh is closed here
print "closed again:\t$.\n";

__END__

Output:
two reads:      2
closed file:    2
open again:     0
one read:       1
closed again:   1