Correction to bell shell alias.

.bashrc

@@ -93,7 +93,7 @@ alias jt='json_tool'
 alias http-server='python3 -m http.server 8080'
 alias dd='monitor dd status=progress'
 alias screenshot-cleanup='find "$HOME/Pictures" -name "Screenshot from *.png" -delete'
-alias bell='printf \a'
+alias bell="printf '\a'"
 command -v notify-send > /dev/null || alias notify-send='bell'
 
 urlencode () {