ET-C02YQH25LVCF:sc-returns aditya.verma$ rbenv install 2.0.0-p648
Downloading ruby-2.0.0-p648.tar.bz2...
-> https://cache.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p648.tar.bz2
Installing ruby-2.0.0-p648...
WARNING: ruby-2.0.0-p648 is past its end of life and is now unsupported.
It no longer receives bug fixes or critical security updates.
ruby-build: using readline from homebrew
Thats it, it just hangs there for eternity.
RUBY_CONFIGURE_OPTS=--with-readline-dir="$(brew --prefix readline)" rbenv install 2.0.0
This worked for me, posting the answer so that one in future could save some time.
I thought it had stuck when in fact I had to wait just a little bit. The process shows no sign of any activity and my CPU was not very busy for quite some time. Get a coffee before searching for a solution, installation took almost 5 minutes in my case.
I let my machine run for about 15 minutes and it eventually completed.
I found out that the Readline library is a command line editor by GNU. The Build Errors analytics on Homebrew are also pretty encouraging so I'd advise people to let it run.
I'm not sure what rbenv was using it for but I believe we should just let it do it's job.