UNIX for Dummies Questions & Answers

I am having problems scripting in UNIX. I am currently attending school and for the first time I am being introduced to scripting. My problem is I am supposed to enhance the spell_check by adding a third optional argument. The third argument is to specify a list of words to be added to the output of spell_check. What I have so far is

if [ $# -ne 2 ]
then
echo "Usage: spell_check steph1 steph2" 1>&2
echo "steph1: list of correct spellings" 1>&2
echo "steph2: file to be checked" 1>&2
exit 1
fi


if [ ! -r "$1" ]
then
echo "spell_check: $1 is not readable" 1>&2
exit 1
fi

if [ ! -r "$2" ]
then
echo "spell_check: $2 is not readable" 1>&2
exit 1
fi

spell < "$2" |
while read line
do
if grep "$line" "$1" > /dev/null
then
:
else
echo "$line"
fi
done

If someone could help me with this I would really appriciate it.
THANK YOU!!

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