# Home of the gems?

**URL:** <https://www.ruby-forum.com/t/home-of-the-gems/49834>\
**Category:** Ruby\
**Created:** [December 9, 2005, 3:12am UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834 "2005-12-09T03:12:31Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 3:12am UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/1 "2005-12-09T03:12:31Z")

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I’m trying to understand how gems are loaded. Please help.

A little background:

I decided to do some rails development work on a debian system. I didn’t  
think rails was up to date, so I tried to do a ‘gem update rails’. This  
failed because I did not have root access. So I installed the gems  
locally.  
Everthing seemed fine.

I later deleted the local gem directory. Now:

- “gem list” says there are no gems.
- “gemwhich rails” says "can’t find rails.
- The application runs fine.

By now it is clear to me that there are gems installed in the default  
location. I would like to override this with a local install. I don’t  
understand how the load path is determined.

Thanks for your help.

-Kelly

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<div class="post-metadata">

**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 5:52am UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/2 "2005-12-09T05:52:11Z")

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railsinator wrote:

> I’m trying to understand how gems are loaded. Please help.
> 
> A little background:
> 
> I decided to do some rails development work on a debian system. I didn’t  
> think rails was up to date, so I tried to do a ‘gem update rails’. This  
> failed because I did not have root access. So I installed the gems  
> locally.  
> Everthing seemed fine.
> 
> I later deleted the local gem directory. Now:
> 
> - “gem list” says there are no gems.
> - “gemwhich rails” says "can’t find rails.
> - The application runs fine.
> 
> By now it is clear to me that there are gems installed in the default  
> location. I would like to override this with a local install. I don’t  
> understand how the load path is determined.
> 
> Thanks for your help.

‘gem env’ will give you some information about your gem environment.  
You can control the details here via environment variables:

GEM\_HOME – Path to gem repository where gems are installed by  
default.  
GEM\_PATH – List of paths of gem repositories to be searched.

– Jim W.

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<div class="post-metadata">

**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 7:05pm UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/3 "2005-12-09T19:05:07Z")

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Thanks for getting back to me Jim. Please bear with me as I try to  
understand how this works.

If I do “gem env” I get a stack trace:

kfelkins@lurch:~/bin$ gem env  
/usr/local/lib/site\_ruby/1.8/rubygems.rb:194:in `report_activate_error': Could not find RubyGem sources (> 0.0.0) (Gem::LoadError) from /usr/local/lib/site_ruby/1.8/rubygems.rb:136:in`activate’  
from /usr/local/lib/site\_ruby/1.8/rubygems.rb:37:in  
`require_gem_with_options' from /usr/local/lib/site_ruby/1.8/rubygems.rb:31:in`require\_gem’  
from  
/usr/local/lib/site\_ruby/1.8/rubygems/remote\_installer.rb:403:in  
`sources' from /usr/local/lib/site_ruby/1.8/rubygems/gem_commands.rb:897:in`execute’  
from /usr/local/lib/site\_ruby/1.8/rubygems/command.rb:49:in `invoke' from /usr/local/lib/site_ruby/1.8/rubygems/cmd_manager.rb:92:in`process\_args’  
from /usr/local/lib/site\_ruby/1.8/rubygems/cmd\_manager.rb:65:in  
`run' from /usr/local/lib/site_ruby/1.8/rubygems/gem_runner.rb:9:in`run’  
from /home/kfelkins/bin/gem:17  
kfelkins@lurch:~/bin$

Still, my rails app will run when I start it with script/server.

So clearly there are a set of gems installed somewhere. These were  
likely  
installed via the debian package management system. So how are gems  
found?

kfelkins@lurch:~/bin$ echo $GEM\_HOME  
/home/kfelkins/gem-repository  
kfelkins@lurch:~/bin$ ls -l $GEM\_HOME  
total 16  
drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 cache  
drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 doc  
drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 gems  
drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 specifications  
kfelkins@lurch:~/bin$ cd $GEM\_HOME/gems  
kfelkins@lurch:~/gem-repository/gems$ ls  
kfelkins@lurch:~/gem-repository/gems$ echo $GEM\_PATH  
kfelkins@lurch:~/gem-repository/gems$

Thanks again.

-Kelly

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<div class="post-metadata">

**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 7:53pm UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/4 "2005-12-09T19:53:05Z")

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railsinator wrote:

> Thanks for getting back to me Jim. Please bear with me as I try to  
> understand how this works.
> 
> If I do “gem env” I get a stack trace:
> 
> kfelkins@lurch:~/bin$ gem env  
> /usr/local/lib/site\_ruby/1.8/rubygems.rb:194:in `report_activate_error': Could not find RubyGem sources (> 0.0.0) (Gem::LoadError) from /usr/local/lib/site_ruby/1.8/rubygems.rb:136:in`activate’  
> from /usr/local/lib/site\_ruby/1.8/rubygems.rb:37:in  
> `require_gem_with_options' from /usr/local/lib/site_ruby/1.8/rubygems.rb:31:in`require\_gem’  
> from  
> /usr/local/lib/site\_ruby/1.8/rubygems/remote\_installer.rb:403:in  
> `sources' from /usr/local/lib/site_ruby/1.8/rubygems/gem_commands.rb:897:in`execute’  
> from /usr/local/lib/site\_ruby/1.8/rubygems/command.rb:49:in `invoke' from /usr/local/lib/site_ruby/1.8/rubygems/cmd_manager.rb:92:in`process\_args’  
> from /usr/local/lib/site\_ruby/1.8/rubygems/cmd\_manager.rb:65:in  
> `run' from /usr/local/lib/site_ruby/1.8/rubygems/gem_runner.rb:9:in`run’  
> from /home/kfelkins/bin/gem:17  
> kfelkins@lurch:~/bin$
> 
> Still, my rails app will run when I start it with script/server.
> 
> So clearly there are a set of gems installed somewhere. These were  
> likely  
> installed via the debian package management system. So how are gems  
> found?
> 
> kfelkins@lurch:~/bin$ echo $GEM\_HOME  
> /home/kfelkins/gem-repository  
> kfelkins@lurch:~/bin$ ls -l $GEM\_HOME  
> total 16  
> drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 cache  
> drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 doc  
> drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 gems  
> drwxrwxr-x 2 kfelkins genome 4096 2005-12-08 17:15 specifications  
> kfelkins@lurch:~/bin$ cd $GEM\_HOME/gems  
> kfelkins@lurch:~/gem-repository/gems$ ls  
> kfelkins@lurch:~/gem-repository/gems$ echo $GEM\_PATH  
> kfelkins@lurch:~/gem-repository/gems$

Ok, it looks like you no longer have the system gem repository in your  
GEM\_PATH. Gem can’t find its sources gem.

Try adding the original repository to the GEM\_PATH. Perhaps something  
like this:

export GEM\_PATH=/usr/local/lib/ruby/gems/1.8

(you might need to tweek the directory for your local system).

Once you add that line, gems should search both your $GEM\_HOME  
repository and the GEM\_PATH repository. You can add more repositories  
to GEM\_PATH if you wish.

– Jim W.

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<div class="post-metadata">

**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 8:50pm UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/5 "2005-12-09T20:50:31Z")

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railsinator wrote:

> I think rails can find the gems. Do you know how rails does it?
> 
> I’m not certain that rails uses gems _after_ an application has been  
> created. Rails is installed as a collection of gems, but I guess it is  
> possible that when you create a rails application all of the required  
> libraries are copied or linked, though I doubt it.

hard to say without knowing more details. Some possibilities are:

(1) Rails comes in non-gem versions, is one of those installed?  
(2) GEM\_HOME is an environment variable. Although your interactive  
shell was messed up, it could be that rails is running in a different  
window with its own, properly setup, GEM\_HOME value. (Possibly started  
before you changed it).

– Jim W.

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<div class="post-metadata">

**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 8:05pm UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/6 "2005-12-09T20:05:26Z")

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I think rails can find the gems. Do you know how rails does it?

I’m not certain that rails uses gems _after_ an application has been  
created. Rails is installed as a collection of gems, but I guess it is  
possible that when you create a rails application all of the required  
libraries are copied or linked, though I doubt it.

-kelly

---

<div class="post-metadata">

**Author:** ![railsinator](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ac8455/32.png) [@railsinator](https://www.ruby-forum.com/u/railsinator)\
**Post date:** [December 9, 2005, 9:28pm UTC](https://www.ruby-forum.com/t/home-of-the-gems/49834/7 "2005-12-09T21:28:48Z")

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Thanks Jim. I’m going to go with your #1. Since this is a debian system,  
my  
guess is rails was installed using apt-get. I also run debian on my  
personal  
systems but I don’t use apt-get to install rails – I use gems.

-Kelly