You can do something similar using the show-mode-in-prompt option:<p><pre><code>  show-mode-in-prompt
    If set to `on&#x27;, add a character to the beginning of the prompt indicating
    the editing mode: emacs (`@&#x27;), vi command (`:&#x27;), or vi insertion (`+&#x27;).
    The default value is `off&#x27;.
</code></pre>
Unfortunately it&#x27;s currently hardcoded to only use the &#x27;+&#x27; and &#x27;:&#x27; chars, and to only display at the beginning of the prompt.<p>Chet accepted a patch I submitted for custom indicators, and this will be coming in bash 4.4&#x2F;readline 7.0:
<a href="http:&#x2F;&#x2F;thread.gmane.org&#x2F;gmane.comp.shells.bash.bugs&#x2F;22580&#x2F;focus=22613" rel="nofollow">http:&#x2F;&#x2F;thread.gmane.org&#x2F;gmane.comp.shells.bash.bugs&#x2F;22580&#x2F;fo...</a><p>I have patched versions of bash 4.3&#x2F;readline 6.3 available on github (the bash page has gifs showing the functionality in action):
<a href="https:&#x2F;&#x2F;github.com&#x2F;calid&#x2F;bash" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;calid&#x2F;bash</a>
<a href="https:&#x2F;&#x2F;github.com&#x2F;calid&#x2F;readline" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;calid&#x2F;readline</a><p>Note that the &#x27;\m&#x27; escape hasn&#x27;t been accepted into the mainline yet, so as of now the custom indicators will still only display at the beginning of the prompt in the new versions.