Today, at the low end of the communication protocols, we find I²C (for ‘Inter-Integrated Circuit’, protocol) and SPI (for ‘Serial Peripheral Interface’). Both protocols are well-suited for communications between integrated circuits, for slow communication with on-board peripherals. At the roots of these two popular protocols we find two major companies – Philips for I²C and Motorola for SPI – and two different histories about why, when and how the protocols were created.

Although the Readline library comes with a set of default keybindings, it is possible to modify these by putting commands into a .inputrc file, typically in the home directory. The name of this file is taken from the value of the shell variable INPUTRC. If that variable is unset, the default is ~/.inputrc If that file does not exist or cannot be read, the ultimate default is /etc/inputrc