bash - 库存簿管理中的 shell 编程

Question

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 "
}

我想显示“书已经存在”，以防输入文件中类似名称的书

Answer 1

在添加图书之前，请检查它是否存在：

     grep "$title" BookDB.txt >/dev/null 2>&1
     rc=$?

     if [[ "$rc" != 0 ]]; then
        echo $title:$author:$price:$available:$sold >> BookDB.txt
        echo $BookDB "New book title ' $title ' added successfully "
     else
        echo "The book $title already exists."
     fi

Answer 2

function add_new_book
{
  echo "1) add_new_book"
  echo -n "Title :"
    read title
    grep -iqs "^$title:" BookDB.txt && echo "THE BOOK ALREADY EXISTS" && return

  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 "
}