$line = "foo  bar";
print ++$i, ". $_\n" for split / /, $line;

##</code><code>##

split /\s+/, $line

##</code><code>##

$line = "  foo   bar  ";

##</code><code>##

split " ", $line

##</code><code>##

perl -MO=Deparse -e 'split " "'
split(/\s+/, $_, 0);

##</code><code>##

perl -MO=Deparse -e 'split /\s+/'
split(/\s+/, $_, 0);