### 31.5 Readline vi Mode

While the Readline library does not have a full set of `vi` editing functions, it does contain enough to allow simple editing of the line. The Readline `vi` mode behaves as specified in the posix standard.

In order to switch interactively between `emacs` and `vi` editing modes, use the command `M-C-j` (bound to emacs-editing-mode when in `vi` mode and to vi-editing-mode in `emacs` mode). The Readline default is `emacs` mode.

When you enter a line in `vi` mode, you are already placed in `insertion' mode, as if you had typed an ‘`i`’. Pressing <ESC> switches you into `command' mode, where you can edit the text of the line with the standard `vi` movement keys, move to previous history lines with ‘`k`’ and subsequent lines with ‘`j`’, and so forth.