rbenv install - executable host ruby is required

Question

I am trying to install ruby 2.2.0-dev using rbenv into my Ubuntu 13.10 development laptop. I have removed all previous ruby and gem installations. Now, when I try to install ruby I get the following error.

mark@Inspiron-1564:~/.rbenv$ rbenv install 2.2.0-dev
Cloning https://github.com/ruby/ruby.git...
Installing ruby-2.2.0-dev...

BUILD FAILED

Inspect or clean up the working tree at /tmp/ruby-build.20140119161217.4141
Results logged to /tmp/ruby-build.20140119161217.4141.log

Last 10 log lines:
/tmp/ruby-build.20140119161217.4141 ~/.rbenv
Cloning into 'ruby-2.2.0-dev'...
Checking connectivity... done
/tmp/ruby-build.20140119161217.4141/ruby-2.2.0-dev /tmp/ruby-build.20140119161217.4141 ~/.rbenv
executable host ruby is required. use --with-baseruby option.; false -C ./tool get-config_files config.guess
executable host ruby is required. use --with-baseruby option.; false -C ./tool get-config_files config.sub
configure: error: cannot run /bin/bash tool/config.sub

Answer 1

tl;dr

you need a non-dev version (i.e. 2.2.0) installed (also using rbenv) before you can have the dev version.

---

As of rbenv 1.0.0 you don't need to have ruby from the repository (e.g. using apt-get) installed on your machine to be have any *-dev version installed. However, it is required to have a non-dev version already installed (through rbenv) before installing any *-dev version.

Answer 2

You can't use rbenv without a native installation of ruby in the machine. You should install ubuntu's ruby (sudo apt-get install ruby) so rbenv will have a base version to work with. If you can run ruby -v then you're all set.