I want to switch to vi editing mode in a readline environment.  But I don't want to use 'set -o vi'.  I want to temporarily switch using a keyboard shortcut.  The man page says I can do this with M-C-j.  But that doesn't work for me.  I'm using Ubuntu and an xterm.  Doesn't work under gnome-terminal either.
How do I switch to vi editing mode in readline?
bash;readline
Bash explicitly disables this and a few other Readline shortcuts.  See the initialize_readline() function in the bash source code (http://www.catonmat.net/download/bashline.c):   /* In Bash, the user can switch editing modes with set -o [vi emacs],      so it is not necessary to allow C-M-j for context switching.  Turn      off this occasionally confusing behaviour. */   rl_unbind_key_in_map (CTRL('J'), emacs_meta_keymap);   rl_unbind_key_in_map (CTRL('M'), emacs_meta_keymap);#if defined (VI_MODE)  rl_unbind_key_in_map (CTRL('E'), vi_movement_keymap);#endifI don't seem to be able to override this behavior using the Readline configuration file (.inputrc).