do BLOCK while COND;

##</code><code>##

do BLOCK

##</code><code>##

EXPR while COND;

##</code><code>##

$ perl -E'last while 1;'
Can't "last" outside a loop block at -e line 1.

$ perl -E'do { last; };'
Can't "last" outside a loop block at -e line 1.

$  perl -E'do { last; } while 1;'
Can't "last" outside a loop block at -e line 1.

##</code><code>##

for (;;) {
    my $line = <KNOME>;
    last if not defined $line;

    chomp $line;
    my ($chr, $pos) = split(/\t/, $line);
    $chr += 0;  # Numify.
    $pos += 1;  # Make 1-based

    last if $pos >= $kgArr[1];

    print OUTFILE "$chr\t$pos\n";
}

##</code><code>##

while (defined( my $line = <KNOME> )) {
    chomp $line;
    my ($chr, $pos) = split(/\t/, $line);
    $chr += 0;  # Numify.
    $pos += 1;  # Make 1-based

    last if $pos >= $kgArr[1];

    print OUTFILE "$chr\t$pos\n";
}