CODEWITHSUNDEEP
bash
user3001342
user3001342

Reputation: 11

Bash printing of text file

Inside my text file, I have a list of books, that goes by title,author,price. For example,

Harry Potter - The Half Blood Prince:J.K Rowling:39.99

Title, author and price are all separated with ":" delimiter.

I have two options, search by title and/or author. An enter is read if either one is left empty. 

elif [ "$title" == "" ] 
then
    count=`grep -c "$author" Books.txt`
    echo "Found $count Records: " 
    awk "/$author/" Books.txt       
    if [ "$count" -eq 0 ]
    then
        echo "Book not found!"
    fi
elif [ "$author" == "" ] 
then
    count=`grep -c "$title" Books.txt`
    echo "Found $count Records: " 
    awk "/$title/" Books.txt        
    if [ "$count" -eq 0 ]
    then
        echo "Book not found!"
    fi

There is no problem search and printing but if I invert the order, typing the author's name into the title field, I will still get the same result. What's up?

Upvotes: 0

Views: 95

Answers (1)

bryn
bryn

Reputation: 3325

Well, you have two pieces of identical code that just checks whether a string is part of a line. If you enter the author into the title field, you end up doing this:

awk "/$title/" Books.txt

Which, when 'title' is set to the name of an author, does exactly the same thing as this (given that $author is an authors name here too):

awk "/$author/" Books.txt

To improve/make it more precise you could tell awk to count only for a given column, i.e.:

author="J.K Rowling"
awk -F ':' -v author="$author" '$2 == author' Books.txt

UPDATE

Your question is "what's up", which I have explained, but here is some kind of practical solution for you (just updating your code here):

elif [ "$title" == "" ] 
then
    count=$( awk -v author="$author" -F ':' '$2 == author { c++ } END { print c }' Books.txt )
    if [ "$count" -eq 0 ]
    then
        echo "Book not found!"
    else
        echo "Found $count Records: " 
        awk -v author="$author" -F ':' '$2 == author' Books.txt
    fi
elif [ "$author" == "" ] 
then
    count=$( awk -v title="$title" -F ':' '$2 == title { c++ } END { print c }' Books.txt )
    if [ "$count" -eq 0 ]
    then
        echo "Book not found!"
    else
        echo "Found $count Records: " 
        awk -v title="$title" -F ':' '$2 == title' Books.txt
    fi

...I haven't actually run all this code, but 'it should work' ;-)

Upvotes: 1

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