cat

echo "Le first file name, good sir/lass: "
read file1

echo "How about the second file name, good sir/lass: "
read file2

content1=`cat $file1`
content2=`cat $file2`

content3=`expr $content1 / $content2`

echo "$content3" > $file1

echo "The answer is $content3. The result has also been stored on the first file named $file1."