Environment Variables
Environment variables are a set of key-value pairs made available to running programs and processes on a computer. They allow configuration of different aspects of an application without having to directly modify the application code.
Environment variables work by storing data like directory paths, credentials, or settings as variables that the operating system makes accessible to applications. For example, the PATH variable contains directories to look in for executable programs. When you run a command, the OS checks PATH to find the program. Another common one is HOME which contains the path to the user's home directory. Applications can access these variables at runtime to determine where to save files, where to look for resources, and other behavior. In devops, environment variables are useful for configuring containers and software without baking credentials into code. They allow flexibility to run the same app in different environments. For example, a container can access a DATABASE_URL variable to connect to the right database for local development vs production.