[Rubygems-developers] Can anyone shed a little light on executable gems for me?

Stephen Bannasch stephen.bannasch at deanbrook.org
Sat Dec 29 00:02:34 EST 2007

>It seems to me that something has changed quite a bit about how executable gems are handled in the last few versions? 
>In the past there was a $GEM_HOME/bin directory but it doesn't seem to be there any more?  Instead it seems the executable files for installed gems end up in the same place that the gem command exits?  Is this right?  Or am I off base on this?
>The reason I ask is I'm left wondering how best to separate a Ruby 1.8 environment from a Ruby 1.9 environment so that they can each have a for example a 'rails' gem installed and work in both environments at the same time but with separate gems?


I install ruby 1.9 into a whole different directory and the gems also live there. If I am writing code for 1.9

This is how it works on my MacOS X 10.4.11 system.

My source for Ruby 1.9 lives here:


The Ruby 1.9 install lives here:


I build the source using these configure parameters:

./configure --prefix=/Users/stephen/dev/ruby/1.9_trunk/ --enable-pthread --with-readline-dir=/usr/local --enable-shared

[I've already got an up-to-date copy of readline built and installed in /usr/local]

Following this with make; make install creates my ruby 1.9 installation here ~/dev/ruby/1.9_trunk.

I set my path accordingly by executing this after I cd into ~/dev/ruby/1.9_trunk:

  export PATH=`pwd`/bin:$PATH

I've now got a pristine new ruby 1.9 environment there. Gems installed there won't conflict at all with the Ruby 1.8.6 p111 I have installed in /usr/local. I do something very similar for my JRuby installs.

[~/dev/ruby/1.9_trunk]$ ruby --version
ruby 1.9.0 (2007-12-29 revision 0) [i686-darwin8.11.1]

[~/dev/ruby/1.9_trunk]$ gem environment
RubyGems Environment:
  - RUBYGEMS VERSION: 1.0.1 (1.0.1)
  - RUBY VERSION: 1.9.0 (2007-12-29 patchlevel 0) [i686-darwin8.11.1]
  - INSTALLATION DIRECTORY: /Users/stephen/dev/ruby/1.9_trunk/lib/ruby/gems/1.9.0
  - RUBYGEMS PREFIX: /Users/stephen/dev/ruby/1.9_trunk/lib/ruby
  - RUBY EXECUTABLE: /Users/stephen/dev/ruby/1.9_trunk/bin/ruby
    - ruby
    - x86-darwin-8
     - /Users/stephen/dev/ruby/1.9_trunk/lib/ruby/gems/1.9.0
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
     - "rdoc" => "--template jamis --inline-source --line-numbers"
     - http://gems.rubyforge.org

[~/dev/ruby/1.9_trunk]$ gem list --local

*** LOCAL GEMS ***

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