inputrc

inputrc is the configuration file used by the GNU Readline library to customize line editing and input behavior for interactive programs. Readline powers many shells and applications, including Bash and Python's interactive interpreter, enabling customizable keybindings, history navigation, and other editing features.

Location and scope: System-wide settings are typically read from /etc/inputrc, with some systems providing a default in /usr/share/readline/inputrc. User-specific preferences reside in ~/.inputrc. When both files exist, the user file generally takes precedence, allowing per-user customization that overrides system defaults.

Syntax and usage: The file uses a compact command language with two main forms: set directives and bind directives. Set directives adjust Readline options (for example, editing mode or completion behavior), while bind directives map key sequences to Readline functions. Lines starting with a hash or blank lines are treated as comments or separators in many implementations. Key sequences are enclosed in quotes and may include escape sequences.

Common options and bindings: Typical options include set editing-mode emacs or set editing-mode vi to choose the editing style, set completion-ignore-case On to make tab completion case-insensitive, and set bell-style visible or audible to control the visual or audio bell. Bindings pair a quoted key sequence with a Readline function, such as bind '"\C-a": beginning-of-line' to move the cursor to the start of the line, or bind '"\C-e": end-of-line' for the end.

Reloading and scope of effect: Changes to inputrc affect programs that use Readline and are started after the file is read. Some programs can re-read the file without restarting, while others require a new session. The file is plain text and widely used across Unix-like systems to tailor command-line editing.