Furthermore, one could finally do $ run_readline_command dump-variables | grep bell prefer-visible-bell is set to `on' bell-style is set to `audible'
which is rather impossible, even if one does bind unbound commands. Currently one must probably use script(1), bind the key, and then exit and grep the typescript. Or one must be in X-windows, bind the key, and the copy the output of pushing the bound key into a file, and the grep that. So my proposal would save a rather large amount of work this time. (No, don't really call it exactly run_readline_command.)
