What are Environment Variables in Windows 10?

In Windows 10, as in other operating systems, environment variables are a set of dynamic values that provide information to running processes and applications about the environment in which they are operating. 

These variables contain information about system paths, user settings, and other configuration options that affect how software behaves. Environment variables are used to store information that can be accessed and used by applications and scripts.

Here are a few key aspects of environment variables in Windows 10:

1. System Environment Variables: 

These variables are global and apply to the entire operating system. They are set by the Windows operating system and can include values such as system paths, system directories, and configuration settings that are common to all users.

2. User Environment Variables: 

These variables are specific to each user profile on the system. They can be customized by individual users to set preferences and configuration options that apply only to their account.

3. Common Environment Variables: 

Some environment variables, like "PATH," are used by both the system and users. The "PATH" variable, for example, defines a list of directories where the operating system looks for executable files when a command is issued. This is crucial for running commands and applications from the command prompt or terminal.

4. Accessing Environment Variables: 

You can access environment variables in Windows using various methods, including:

   - Command Prompt: Use the "echo" command to display the value of an environment variable. For example, `echo %USERNAME%` will display the current user's username.

   - PowerShell: In PowerShell, you can use `$env:VARIABLE_NAME` to access the value of an environment variable. For example, `$env:PATH` retrieves the value of the "PATH" variable.

   - System Properties: You can view and edit environment variables through the System Properties dialog. Right-click on "This PC" or "Computer" (depending on your Windows version), select "Properties," and then click on "Advanced system settings." In the System Properties window, you'll find the "Environment Variables" button.

5. Editing Environment Variables: 

You can add, modify, or remove environment variables as needed. Be cautious when making changes, especially to system-level variables, as it can impact the functioning of your system and applications.

Environment variables are essential for configuring and customizing your Windows environment, and they are used by various applications and scripts to determine how they should behave based on the context in which they are running.