my %hash = qw/ one 1 two 2 three 3 four 4 five 5 /;

print "pass 1-----\n"; once_thru();
print "pass 2-----\n"; once_thru();

sub once_thru {
    while ( my ( $k, $v ) = each %hash ) {
        last if $k eq 'five';
        print "$k $v\n";
    }
}
__END__
pass 1-----
three 3
pass 2-----
one 1
two 2
four 4