Command line editing

LAMP utilizes the GNU command line editing interface through the readline module. The readline module uses Emacs-style editing commands by default. However, switching to vi-style line editing provides enhanced text manipulation capabilities.

Customization of readline behavior requires adding commands to the readline initialization file. The file location is defined by the ‘INPUTRC’ environment variable. When this variable is unset, the default location becomes ‘~/.inputrc’.

Readline vi mode

To enable vi-style interface, add the following line to ‘~/.inputrc’ (create the file if it does not exist):

set editing-mode vi

Readline vi mode starts in insertion mode, similar to pressing ‘i’ in the vi editor. Pressing <ESC> enters normal mode, enabling text editing with standard vi movement commands. The ‘k’ key navigates to previous command history, while ‘j’ moves to subsequent commands.

Useful vi key bindings for command line editing

w/W/b/B	Move by one word forward/backward
0/$	Move to start/end of line
daw/caw	Delete/Change a word
cc	Change entire line
f/F	Forward/Backward search for specific character

Example: Modifying execute show ip mrib route -i to execute show ipv6 mrib route -i using the ‘find’ command:

Cursor position in vi mode

Keystroke	Command line (|| shows cursor position)
<ESC>	execute -i show ip mrib rout|e|
Fp	execute -i show i|p| mrib route
av6	execute -i show ipv6 mrib route