There's a new update of the BashSupport plugin available now. It's already available in IntelliJ's plugin downloader and will be available on http://plugins.intellij.net/plugin/?id=4230 in the next few days, I suppose.
In theory it also supports RubyMine and the other products based on the IntelliJ plattform.
Currently there are some unsolved problems which prevent this, though.
- Path/file completion
- Configurable support for Bash version 4.0.
- Expansions now can be replaced with the evaluated result.
- Ctrl+Q on function definitions and calls now shows the comment block right before the definition of the requested function.
- Improved parser.
If there are any obvious bugs or missing features, please let me know.