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Rust Environment Variables

Using Environment Variables

Rust environment variables use std::env for configuration.

Introduction to Environment Variables in Rust

Environment variables are a set of dynamic values that can affect the way running processes behave on a computer. In Rust, they are often used for configuration purposes, allowing you to modify the behavior of an application without changing its source code.

Rust provides the std::env module, which allows you to interact with environment variables easily. This guide will cover how to read, set, and remove environment variables using Rust.

Reading Environment Variables

To read an environment variable in Rust, you can use the std::env::var function. This function returns a Result, which means it will return an error if the environment variable is not found.

Setting Environment Variables

Setting an environment variable within a Rust program can be done using the std::env::set_var function. Note that changes made to environment variables this way only affect the current process and its children.

Removing Environment Variables

If you need to remove an environment variable, you can use the std::env::remove_var function. Like setting, removal only affects the current process and its child processes.

Common Use Cases for Environment Variables

Environment variables are commonly used for:

  • Configuration: Storing settings such as database URLs, API keys, and other configuration values.
  • Secret Management: Keeping sensitive information out of the source code.
  • Environment Differentiation: Managing different settings for development, testing, and production environments.

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