CODEWITHSUNDEEP
bashvalidationunixawk
debal
debal

Reputation: 1017

Validations using AWK

a=1

echo -n "Enter book id: "; read book_id;
while [ $a -eq 1 ]
do
a=$(awk '{ if($3 == "$book_id") print 1; else print 0}' exercise1_data.txt)
echo $a
if [ $a -eq 1 ]; then
echo -n "Please enter unique book id: "; read book_id
fi
done

I am trying to check if the book id entered by the user is unique or not. What I am doing is checking in the file "exercise1_data.txt" if there is any instance of "book_id". The while loop is to be executed until the user inputs a unique book id.

I am getting an error Too many arguments

Upvotes: 1

Views: 244

Answers (1)

Chris Seymour
Chris Seymour

Reputation: 85883

Firstly fixing the awk:

You need to pass shell variables to awk using the -v option:

awk -v b_id="$book_id" '$3==b_id{print 1;exit}END{print 0}' exercise1_data.txt

Also if $3==b_id you should print 1 and exit as a match is found. Only print 0 when we reach the end of file (no match found).

Secondly the script:

$ cat file
book_1 orielly 100
book_2 wiley 101

Script:

#!/bin/bash

a=1

while [ "$a" -eq 1 ]; do
    echo -n "Please enter unique book id: "
    read book_id
    let a=$(awk -v b_id="$book_id" '$3==b_id{print 1;exit}END{print 0}' file)
    echo "$a"
done

Demo:

$ bash script.sh
Please enter unique book id: 100
1
Please enter unique book id: 101 
1
Please enter unique book id: 102
0

Notes:

  • Always quotes your shell variables.

  • You are using whitespace as a field separator in the book file this won't be flexible i.e books titles, authors ect all have whitespace.

Upvotes: 2

Related Questions