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

If you are ok with writing a function for this purpose, it can be pretty convenient.

This solution uses the ${!VAR_NAME} syntax to check whether the variable is empty and has the added benefit of telling you which variable names are empty.

check_vars()
{
    var_names=("$@")
    for var_name in "${var_names[@]}"; do
        [ -z "${!var_name}" ] && echo "$var_name is unset." && var_unset=true
    done
    [ -n "$var_unset" ] && exit 1
    return 0
}

# Usage for this case
check_vars DB HOST DATE
echo "You are good to go"