How can I check if an environment variable exists in Ruby?

How can I check if an environment variable exists in Ruby?

You can use the ENV hash in Ruby to check for environment variables. For example, ENV['VARIABLE_NAME'] will return nil if the variable doesn't exist.

Can you show me a code example?

Sure! Here's a simple example:

if ENV['MY_VAR']
  puts 'MY_VAR exists!'
else
  puts 'MY_VAR does not exist.'
end

What if I want to set a default value if it doesn't exist?

You can use the || operator to set a default value. For example:

my_var = ENV['MY_VAR'] || 'default_value'

Thanks! Is there a way to list all environment variables?

Yes! You can list all environment variables by using ENV.each do |key, value| and printing them out.