62.11. Summary

On early UNIX systems, terminals were real hardware devices connected to a computer via serial lines. Early terminals were not standardized, meaning that different escape sequences were required to program the terminals produced by different vendors. On modern workstations, such terminals have been superseded by bit-mapped monitors running the X Window System. However, the ability to program terminals is still required when dealing with virtual devices, such as virtual consoles and terminal emulators (which employ pseudoterminals), and real devices connected via serial lines.

Terminal settings (with the exception of the terminal window size) are maintained in a structure of type termios, which contains four bit-mask fields that control various terminal settings and an array that defines the various special characters interpreted by the terminal driver. The tcgetattr() and tcsetattr() functions allow a program to retrieve and modify the terminal settings.