function add_new_book
{
echo "1) add_new_book"
echo -n "Title :"
read title
echo -n "Author :"
read author
echo -n "Price :"
read price
echo -n "Qty Available : "
read available
echo -n "Qty Sold : "
read sold
echo $title:$author:$price:$available:$sold >> BookDB.txt
echo $BookDB "New book title ' $title ' added successfully "
}
ファイルから同名の本を入力した場合に「THE BOOK ALREADY EXISTS」と表示させたい