echo " a " | (read x; echo "$x.")

echo " a  b  " | ( read x y ; echo -"$x"-"$y"- )
echo " a  b\ " | ( read x y ; echo -"$x"-"$y"- )
echo " a  b  " | ( read x ; echo -"$x"- )
echo " a  b\ " | ( read x ; echo -"$x"- )

echo " a  b\ " | ( read -r x y ; echo -"$x"-"$y"- )
echo " a  b\ " | ( read -r x ; echo -"$x"- )

echo "\ a  b\ " | ( read -r x y ; echo -"$x"-"$y"- )
echo "\ a  b\ " | ( read -r x ; echo -"$x"- )
echo " \ a  b\ " | ( read -r x y ; echo -"$x"-"$y"- )
echo " \ a  b\ " | ( read -r x ; echo -"$x"- )

echo "A B " > /tmp/IN
unset x y z
read x y z < /tmp/IN
echo 1: "x[$x] y[$y] z[$z]"
echo 1a: ${z-z not set}
read x < /tmp/IN
echo 2: "x[$x]"
rm /tmp/IN