What are environment variables?

Environment variables are essential components in computing that serve as dynamic values which can influence the behavior of running processes and system commands. They provide configuration settings that affect how processes operate and how applications interact with the operating system. For instance, environment variables can specify the location of executable files, define system paths, or determine user preferences.

In many operating systems, environment variables are often used by applications and scripts to retrieve information about the environment in which they are executing. This includes variables like PATH, which tells the system where to find executable files, or HOME, which specifies the user's home directory. The ability to modify these variables can drastically change how an application runs or how commands execute in a shell environment.

The other options do not accurately describe the purpose of environment variables. Constants set by the user refer more to fixed values that do not change during execution, temporary files are used for storage during a process but do not influence behavior, and commands stored for quick access typically involve aliases or shortcuts rather than environment variables. Understanding environment variables is crucial for effective system administration and scripting in a Linux environment.