Ruby shell with custom .inputrc

November 08, 2020

The program irb is an interactive ruby shell. When I run it, the VI navigation keys “HJKL” move the cursor rather than inserting the characters “HJKL”. This looks related to my custom ~/.inputrc file which specifies readline use the VI keybindings, instead of the default emacs keybindings:

# ~/.inputrc
...
set editing-mode vi
...

In certain interactive shells (those that use readline), such as bash and the python shell, this adds modal line editing and VI key navigation that I’m accustomed to in Vim. But it seems that irb doesn’t work correctly with VI editing mode. It’s trying to do something. Switching from insert to normal mode works, and I can use additional VI navigation commands such as work navigation while in normal mode. But “HJKL” navigation doesn’t turn off in insert mode, so I can’t type “HJKL”.

The workaround is to tell irb to ignore ~/.inputrc when launching it:

$ INPUTRC=/dev/null irb