How to check if multiple variables are defined or not in bash

Question

I want to check, if multiple variable are set or not, if set then only execute the script code, otherwise exit.

something like:

if [ ! $DB==\"\" &&a         


        

Answer 1

You can check it also by put the variables name in a file

DB=myDB
HOST=myDB
DATE=myDATE

then test them if currently empty or unset

#!/bin/bash
while read -r line; do
    var=`echo $line | cut -d '=' -f1`
    test=$(echo $var)
    if [ -z "$(test)" ]; then 
        echo 'one or more variables are undefined'
        exit 1
    fi
done