echo -n "word 1: "
read word1
echo -n "word 2: "
read word2
echo -n "word 3: "
read word3
if [ "$word1" = "$word2" -a "$word2" = "$word3" ]
    then
        echo "Match: words 1, 2, & 3"
    elif [ "$word1" = "$word2" ]
    then
        echo "Match: words 1 & 2"
    elif [ "$word1" = "$word3" ]
    then
        echo "Match: words 1 & 3"
    elif [ "$word2" = "$word3" ]
    then
        echo "Match: words 2 & 3"
    else
        echo "No match"
fi