Justed stumbled across CRaSH and although it looks mighty interesting, I'm wondering why a Java developer should invest time & energy into learning (yet another) shell language. What sort of standard- and cool-applications can CRaSH be used for? Is this like a Groovy-version of Jython?
I guess, when the dust settles, I'm looking for CRaSH's "wow" factors. I'm sure they're there, but after spending ~20 minutes perusing the documentation I'm just not seeing them. Thanks in advance!
You could do this with Groovy or others, so that's not a very strong point, but as CRaSH gives you code-level access to the JVM and the processes it runs, it may come in handy to just keep a JVM running and experiment with small code snippets (for instance, using it as a REPL to implement solutions to StackOverflow questions).
The JCR extension would seem potentially useful to supplement this, by giving you shell access to remote repositories, and contains a notion of workspace to separate projects.
I could see this being an interesting use case. I don't know of many good process inspection command-line tools for JVM processes, apart from the JDK-packaged ones. CRaSH might help in interacting with them in novel ways.
For instance, you can use the Attach Mode to attach to a running JVM, and then use the thread command to ls, dump or interrupt threads.
You could also write some additional control commands for non-programmers to use CRaSH to perform routine maintenance and monitoring.
The JCR extension seems to be very interesting as well, as it would give a Java-scriptable access to remote development environments. It could also simply allow content-editors to access and edit remote content, when used in the context of CMS-type apps built on top of a JCR-capable content repository.
An introductory blog post by the CRaSH author, about its use at eXoPlatform. And the fact that it is officially supported by eXoPlatform is an indicator that's it potentially good stuff :)
Not much to read, but of interest: French technologist Didier Girard re-posted it.
Basically, I see it as a power-user or administrator interface to JVM processes, built on top of Groovy and networking protocols. So it combines the power of scripting with a nice facade and some built-in connectors.
I agree with SK-logic: most of this can be done with most JVM-languages, and they provide more and flexibility. But CRaSH might provide a shorter path to achieving such goals.
The same applies to the JCR extension capabilities: you can achieve this by glueing together a few age-old and time-tested tools. But this might be a shorter and simpler path (like commands for the heroku platform, or PaaS services, for instance).