printf 'a\t\tb\tc\n' | ( IFS=$(printf "\t") read a b c;  echo "test 1: .$a. .$b. .$c." )
printf 'a\t\tb\tc\n' | ( IFS=$(printf " \t") read a b c; echo "test 2: .$a. .$b. .$c." )
printf 'a,,b,c\n'    | ( IFS="," read a b c;  echo "test 3: .$a. .$b. .$c." )
printf 'a,,b,c\n'    | ( IFS=" ," read a b c; echo "test 4: .$a. .$b. .$c." )
printf 'a ,, c\n'    | ( IFS=" ," read a b c; echo "test 5: .$a. .$b. .$c." )
printf 'a ,, c d\n'  | ( IFS=" ," read a b c d;     echo "test 6: .$a. .$b. .$c. .$d." )
printf ' a,,b,c,d  ,  ,\n' | ( IFS=" ," read a b c; echo "test 7: .$a. .$b. .$c." )
printf '\t,\ta\t,\tb\tc'   | ( IFS=$(printf " \t,") read a b c d;   echo "test 8: .$a. .$b. .$c. .$d." )
printf '\t\ta\t,\tb\tc'    | ( IFS=$(printf " \t,") read a b c d;   echo "test 9: .$a. .$b. .$c. .$d." )
printf '\t,\ta\t,,\tb\tc'  | ( IFS=$(printf " \t,") read a b c d e; echo "test A: .$a. .$b. .$c. .$d. .$e." )
