environmentVariable

An environment variable is a dynamic value stored by an operating system or runtime environment that can influence the behavior of processes and applications. These variables are typically used to configure system settings, define paths, or pass information to programs at runtime.

Environment variables are set at the operating system level or within a user session and are accessible by processes launched within that environment. Common environment variables include PATH, which specifies directories to search for executable files; HOME or USERPROFILE, which indicate a user's home directory; and TEMP or TMP, which point to temporary storage locations.

They serve as a flexible mechanism to manage system behavior without hardcoding configurations into applications. For example, altering the PATH variable allows the system to recognize new command locations, facilitating software deployment and updates. Similarly, setting environment variables can help customize program behavior based on user preferences or environment-specific needs.

Environment variables vary across operating systems. In Unix-like systems, they are usually managed through shell commands such as export or setenv, while in Windows, they can be managed through system properties or command-line tools like set and setx. These variables are stored in key-value pairs and are typically inherited by child processes, ensuring consistent configuration across a software environment.

Because environment variables are a key component of system and application configuration, they are widely used in scripting, automation, and software deployment to create adaptable and portable systems. However, caution is advised when handling sensitive information stored as environment variables to prevent inadvertent exposure.