How to check if a ENV variable is defined in Ruby

In this tutorial, we are going to learn about how to check if a particular ENV variable is defined or not in Ruby.

Using ENV.has_value?() method

In ruby, we can use the built-in ENV.has_value?() method to check if a ENv variable is defined or not in the system environment variables.

The ENV.has_value?() method takes the string as an argument and checks whether the string exists or not in ENV variable, if a ENV variable is defined it returns “true”; otherwise, it returns “false”.

Here is an example:

ENV["TOTAL"] = "Total"

puts ENV.has_value?("TOTAL")

Output:

true

Second example false case:

puts ENV.has_value?("HELLO")

Output:

false

We can also return some default value if a env variable is not available like this in RUBY.

puts ENV.has_value?("HELLO") ? ENV["HELLO"] : "Default value"