Environment variables are a set of dynamic named values that can affect the way running processes will behave on a computer. They are part of the operating environment in which a process runs. For example, an application may use an environment variable to ascertain the location where it can store temporary files or application configurations.
Purpose of Environment Variables
Environment variables serve various functions in an operating system:
- System Environment Variables: These are set by the system and are used by the operating system to pass configuration information to applications and scripts.
- User Environment Variables: These can be set by the user and are often used to customize the behavior of programs for the user's environment without modifying the application itself.
Common Examples of Environment Variables
Some commonly used environment variables include:
- PATH: Specifies the directories in which the operating system and other scripts find executable files.
- HOME: Indicates the directory path to the current user's home directory.
- TEMP: Provides the temporary directory that programs use to store temporary files.
Manipulating Environment Variables
Environment variables can be managed in several ways through the operating system's interface or command line. For instance:
- In Windows, environment variables can be set through System Properties or using the
setcommand in the Command Prompt. - In Unix/Linux environments, environment variables can be set in the shell, such as Bash or Zsh, using the
exportcommand.
Benefits of Using Environment Variables
Using environment variables offers several benefits, including:
- Flexibility: They allow configurations that could vary between different environments (development, testing, production) without changing code.
- Security: Sensitive information such as API keys can be kept out of source code.
- Convenience: Simplifies setup processes and maintains consistency across multiple environments.
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