The squiggly line character found on computer keyboards is called the "tilde." However, it is informally referred to as the "squiggly" or "twiddle." On keyboards with the U.S. layout, it is usually found near the top left corner above the "Tab" key.
The tilde is used in some languages as a diacritical mark. For example, in Portuguese, it indicates nasalization. The character is also used informally in English as a symbol for "approximately" or "similar to."
The squiggly also finds use in computers. In Unix-like systems, the tilde can be used to return users to the "home" directory when navigating via the terminal. Moreover, different programming languages use the character to serve various purposes. For example, in C, the tilde is a bitwise NOT operator.