You know, I work at the command line all day, and I'm always happy to learn a new trick. But for writing actual scripts, I'd much rather write in Ruby. I don't want to have to use awkward syntax like case statements ending with "esac."
Yes, using Ruby introduces a dependency beyond Unix. But I already use lots of libraries (Rails, Rspec, etc) and tools (ImageMagick, Ghostscript), so I don't see that as a problem, just part of the job.
Indeed, I've long ago adopted the convention to do any remotely advanced scripting in a "real" scripting/programming language (myself, I use Python for this).
Bash scripting is good for running a few commands in a sequence, but in my experience gets unmaintainable and unreadable very quickly, especially if you try to do sane error handling/logging, or operations on non-text data.
Yes, using Ruby introduces a dependency beyond Unix. But I already use lots of libraries (Rails, Rspec, etc) and tools (ImageMagick, Ghostscript), so I don't see that as a problem, just part of the job.