difference awk print $1, .. $NF and print $0

echo "a b c  d" |awk '{print}'

or echo "a b c d" |awk '{print $0}'

retus a b c d.

echo "a b c  d" |awk '{print $1, $2, $3, $4}'

retus a b c d

Are there any ways to simply do $1, $2, $3, $4 as $hoge alteatively.