Removing of specific line in text file

Question

I am working on an option which will be able to remove the line specified if the user types in the exact title and author.

However I will not be able to make it work

Answer 1

Using single quotes does not interpolate variables. Try something like this -

fnRemoveBook()
{
echo "Title: "
read Title
echo "Author: "
read Author

if grep -Fqe "$Title:$Author" BookDB.txt; then
    sed -i "/$Title:$Author/ d" BookDB.txt    # <---- Changes made here
    echo "Book removed successfully!"
else
    echo "Error! Book does not exist!"
fi
}

Answer 2

You're trying to pass a bash variable (two, actually) into a sub-program (sed), but surrounding the expression you're passing in single-quotes, which does no parameter expansion. That means that sed is literally seeing $Title:$Author. Try putting the whole sed expression in double-quotes:

sed -i "/$Title:$Author/d" BookDB.txt

This will allow bash to expand $Title and $Author before they get into sed.