Final answer:
To halt an infinite loop in most command-line environments, pressing the Control key and the C key (Control+C) usually sends an interrupt signal to terminate the running program.
Step-by-step explanation:
To halt an infinite loop, you can generally interrupt the running program by pressing the Control key and the letter C on the keyboard. This key combination sends an interrupt signal (SIGINT) to the program, telling the operating system to terminate the program that is currently running in the foreground of the console or terminal. This is commonly used in command-line environments across different operating systems, such as Windows, Linux, and macOS.
It's important to note that not all programs may respond to this interrupt if they're designed to handle the SIGINT signal differently or if they are in a state where they are not responsive to user input. In some integrated development environments (IDEs), you might have a stop or halt button in the user interface which can be used to terminate the running program.