# Disobedient 'gem env' Causing Rails "undefined method \`gem' **URL:** \ **Category:** Rails\ **Created:** [May 10, 2007, 8:08pm UTC](https://www.ruby-forum.com/t/disobedient-gem-env-causing-rails-undefined-method-gem/103828 "2007-05-10T20:08:12Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![transonik](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/22d042/32.png) [@transonik](https://www.ruby-forum.com/u/transonik)\ **Post date:** [May 10, 2007, 8:08pm UTC](https://www.ruby-forum.com/t/disobedient-gem-env-causing-rails-undefined-method-gem/103828/1 "2007-05-10T20:08:12Z")
I’m setting up on a textdrive shared host, and have installed my gems to a local directory called ‘gems’. I did this by installing the gems on my ubuntu 7.04 system and tar’ing up the ‘gems’ to a like-named directory on the ‘gilford’ (FreeBSD 5.3) shared host. (a trick required because ‘gem update’ or ‘gem install’ busts txd’s memory limit during a zlib inflate of the gem repository hash - that is, memory allocation fails for even the smallest of gems) After setting my GEM\_PATH and GEM\_HOME so that ‘gem query’ reports _only_ my locally installed gems (as expected), and this test: [xxx@gilford ~]$ gem list rubygems \*\*\* LOCAL GEMS \*\*\* rubygems-update (0.9.2) RubyGems Update GEM reports exactly what I expect, I next try ‘gem env’, which nonetheless reports a back-rev gem version( ! ): [xxx@gilford ~/local]$ gem env Rubygems Environment: - VERSION: 0.8.11 (0.8.11) - INSTALLATION DIRECTORY: /users/home/xxx/gems - GEM PATH: - /users/home/xxx/gems - /users/home/xxx/local/lib/ruby/site\_ruby/1.8 - REMOTE SOURCES: - [http://gems.rubyforge.org](http://gems.rubyforge.org) (note that I have removed the ‘gilford’ system’s gem path altogether, in desperation. I’m trying to avoid all of txd’s gems, so that I am certain that only my local stuff is included) So I download the rubygems-0.9.2.tgz and stick it in a ‘local’ directory, and adjust the two GEM paths above, plus my normal shell PATH and LD\_LIBRARY\_PATH to use the ‘local’ bins and libs first. But I still get ‘gem env’ → 0.8.11 The actual ‘gem’ file in the ‘local/bin’ directory is simply some Ruby that does: require ‘rubygems’ Gem.manage\_gems with a few more lines. Surely these lines are run with either GEM\_PATH or the .gemrc path? And I think both of these are right: ‘gem query’ proves ‘GEM\_PATH’ is working, and the next paragraph shows .gemrc works as well. (I also have a consistent .gemrc in my home dir. According to Jim Weirich’s note from Apr 3 2006, I think I’m doing the right thing: [http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/187403](http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/187403) In short: “All gems use GEM\_PATH, except for ‘gem’, which uses .gemrc.” This behavior is supported by a test in which I add or subtract ‘gilford’s’ gem path from my .gemrc: and as expected, my ‘gem env’ output shows only the lines specified in .gemrc. The reason I care so much about what ‘gem env’ says is because when I type “rails -v” I get: /users/home/xxx/gems/bin/rails:15: undefined method `gem’ for main:Object (NoMethodError) which various posts say results from running current ‘rails’ with a back-rev ‘gem’. The shared host ‘gilford’ is running Ruby 1.8.4 ---
**Author:** ![transonik](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/22d042/32.png) [@transonik](https://www.ruby-forum.com/u/transonik)\ **Post date:** [May 10, 2007, 10:10pm UTC](https://www.ruby-forum.com/t/disobedient-gem-env-causing-rails-undefined-method-gem/103828/2 "2007-05-10T22:10:28Z")
‘gemwhich rubygems’ returns -\> /usr/local/lib/ruby/site\_ruby/1.8/ rubygems.rb BAD! But my .gemrc explicitly specifies a gempath of /home/users/xxx/local/ lib/ruby/site\_ruby/1.8 , and this directory does in fact have a different version of ‘rubygems.rb’. So why does ‘gemwhich rubygems’ find a file that is not on any path I know of? (‘require rubygems’ is supposed to employ the same lookup algorithm as ‘gemwhich’) Can anyone explain what it is doing? ---
**Author:** ![transonik](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/22d042/32.png) [@transonik](https://www.ruby-forum.com/u/transonik)\ **Post date:** [May 11, 2007, 12:24am UTC](https://www.ruby-forum.com/t/disobedient-gem-env-causing-rails-undefined-method-gem/103828/3 "2007-05-11T00:24:42Z")
‘rubygems’ itself is found via a Ruby $LOAD\_PATH lookup. As the PickAxe book explains, this can be set by a ‘ruby -I xxx’ invocation. But in the case of ‘gem’ itself, or of ‘rails’, there is no command line ‘-I’ option. So the library lookup path is specified by $RUBYLIB. This is the Ruby analog to C’s $LD\_LIBRARY\_PATH My .bash\_profile now contains: export RUBYLIB=$HOME/gems/local/lib/site\_ruby/1.8 export GEM\_PATH=$HOME/gems export GEM\_HOME=$HOME/gems If I want some of txd’s stock (old) gems, I’d add their path as well.kk See [http://rubygems.org/read/chapter/15](http://rubygems.org/read/chapter/15)