问如何更新书名？

EN

function update_book
{
   #echo "Title: "
   read -p $'Title: ' updatetitle
   #echo "Author: "
   read -p $'Name: ' updatename

  if grep -Fq "${updatetitle}:${updatename}" BookDB.txt
   then
      echo "Book found!"

      if ! [ -f BookDB.txt ] ; then 
touch BookDB.txt
fi

selection=0
until [ "$selection" = "f" ]; do
      echo ""
      echo ""
      echo "Book Update System"
      echo ""
      echo ""
      echo "a) Update title"
      echo "b) Update Author"
      echo "c) Update Price"
      echo "d) Update Qty Available"
      echo "e) Update Qty Sold"
      echo "f) Back to main menu"

      echo -n "Enter your option: "
      read selection
      echo ""
      case $selection in
            a) upd_title;press_enter;;
            b) upd_author;press_enter;;
            c) upd_price;press_enter;;
            d) upd_qty_avail;press_enter;;
            e) upd_qty_sold;press_enter;;
            f) main_menu;press_enter;;
            * ) tput setf 4;echo "Please enter a, b, c, d, e, or f";tput setf 7; press_enter
      esac
    done  

   else
      echo "Error!! Book does not exist!" #not found
   fi   
}

function upd_title
{
  read -p 'New title: ' title
  #awk '/liine/{ print NR; exit }' BookDB.txt
  grep -n 'regex' | sed 's/^\([0-9]\+\):.*$/\1/'
  awk 'NR==n{$1=a}1' FS=":" OFS =":" n=$linenumber a = $title BookDB.txt
  echo "New title successfully updated!!"

}

Advanced Book Inventory System


1) Add new book
2) Remove existing book info
3) Update book info and quantity
4) Search for book by title/author
5) Process a book sold
6) Inventory summary report
7) Quit
Enter your option: 3

Title: The Notebook
Name: Nicholas Sparks
Book found!


    Book Update System


a) Update title
b) Update Author
c) Update Price
d) Update Qty Available
e) Update Qty Sold
f) Back to main menu
Enter your option: a

New title: Notebook