Homebrew not working after I installed 'sudo gem install rails' - ruby-on-rails

After running any homebrew command I get the same error over and over......
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in require': cannot load such file -- extend/module (LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:inrequire'
from /usr/local/Library/Homebrew/global.rb:1:in <top (required)>'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:inrequire'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in require'
from /usr/local/Library/brew.rb:16:in'

The best idea – use rvm.
First of all reinstall homebrew.
Then install rvm:
\curl -sSL https://get.rvm.io | bash -s stable
Then you need to provide ruby version and gemset. Go to app folder and create files .ruby-version and .ruby-gemset (including dot). Then add version and gemset in this files. Simple way to do it via console. In console, go to app directory, then:
echo ruby-2.1.3 >> .ruby-version
echo gemsetname >> .ruby-gemset
Of course, provide ruby version that you need. Gemsetname is often equal to app name. So, if your app is called coolapp, your gemsetname should be coolapp. Smth like this:
echo coolapp >> .ruby-gemset
Now, leave app directory and try to enter it again via console:
cd /path/to/your/app
RVM will generate everything you need automatically and you will see stmth like this:
ruby-2.1.3 - #gemset created /Users/username/.rvm/gems/ruby-2.1.3#coolapp
ruby-2.1.3 - #generating coolapp wrappers..........
Boya! This approach will provide same version and gemset name for every developer because files will be included in git. And that will decrease bug level. Everything you need from this moment, just use:
bundle install
And everything should goes right!

I would recommend using rbenv or rvm to manage your development Ruby version and gems. Editing OS X's system Ruby could cause difficult-to-diagnose problems.
Also, you shouldn't need to sudo to install gems. You need to be very careful when sudoing a command since, again, it could cause difficult-to-diagnose problems with the operating system down the road.
So, I'd recommend you re-install homebrew, then install rbenv from git, then gem install away.

Related

Using rvm bundle install doesn't install rails

I'm freshly using rvm for running a legacy project.
I installed rvm fine. Running which ruby gives the correct rvm version:
/Users/Mahmoud/.rvm/rubies/ruby-2.5.5/bin/ruby
Then running which bundle, also indicates that bundle is using the correct rvm version:
/Users/Mahmoud/.rvm/rubies/ruby-2.5.5/bin/ruby
Now to get my project running, I run bundle install. It's important to stress on the fact that in my Gemfile I have
gem 'rails', '5.0.7'
Running rails s after those steps, gives:
Rails is not currently installed on this system. To get the latest version, simply type:
Running which rails gives:
/usr/bin/rails
implying that the system version and not the rvm version is being used.
echo $PATH shows:
/Users/Mahmoud/.rvm/gems/ruby-2.5.5/bin:/Users/Mahmoud/.rvm/gems/ruby-2.5.5#global/bin:/Users/Mahmoud/.rvm/rubies/ruby-2.5.5/bin:/Users/Mahmoud/.rvm/bin:/Users/Mahmoud/.pyenv/versions/3.7.2/bin:/usr/local/bin:/Users/Mahmoud/.pyenv/bin:/usr/local/opt/openssl#3/bin:/usr/local/opt/openssl#3/bin:/usr/local/opt/libxml2/bin:/usr/local/opt/mysql#5.7/bin:/usr/local/opt/mysql#5.7/bin:/usr/local/opt/mysql#5.7/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Applications/VMware Fusion.app/Contents/Public:/usr/local/MacGPG2/bin:/Library/Apple/usr/bin:/Users/Mahmoud/.ebcli-virtual-env/executables:/usr/local/mysql/bin
My question is, why hasn't rails been installed when I used bundle install? And why is which rails refering to my system and not my rbenv path?
I'll bet your RVM isn't set up correctly and /usr/bin/ appears in your PATH before RVM's bin directory. Run echo $PATH to confirm.
If so, back up your dotfiles for safety and run rvm get head --auto and it should put your PATH right. Logout and log back in or source your dotfiles (source ~/.bash_profile or whatever) and try again.

Install RVM itself without internet connection

I am switching from DJANGO to Rails, but i don't know how to install RVM in PROD environment.
My PROD server is without internet connection, and not possible connect even for a while. And i cannot find a standalone install package of RVM.
Is there any solution for offline RVM installation?
BTW, can rails be installed without internet?
I just spent some time and build a tutorial for the offline mode: https://rvm.io/rvm/offline - it's the first version so feel free to improve it here: https://github.com/wayneeseguin/rvm-site/blob/master/content/rvm/offline.md (Edit button).
Additionally to my first answer another way to do it would be to compile ruby on online machine, then package it, unpack on the other end and add it to PATH on the offline machine.
Way 1 - only Ruby
curl -L https://get.rvm.io | bash -s stable
source $HOME/.rvm/scripts/rvm
rvm install 1.9.3 --movable
rvm prepare 1.9.3
Some information will be displayed, including file name. Copy it to the offline machine and unpack it there, then just add it to PATH:
echo 'PATH=$PATH:${unpacked_dir}/bin' >> ~/.bashrc
Way 2 - whole RVM:
curl -L https://get.rvm.io | sudo bash -s stable
source /usr/local/rvm/scripts/rvm
rvm use 1.9.3 --install
gem install rails -v 3.2.8
rails new rails3
rvm use 1.8.7 --install
gem install rails -v 2.3.14
rails new rails2
tar czf rvm_and_ruby.tgz /usr/local/rvm /etc/rvmrc /profile.d/rvm.sh
Unpack on the offline end:
cd /
sudo tar xzf rvm_and_ruby.tgz
And open a new terminal.
check http://railsinstaller.org/ (for windows and mac) .After then change environment into production mode . In linux this works export RAILS_ENV=production .
If you are using a linux OS, you can always package the app as a debian or rpm archive which will include rails and the dependent gems referred in your Gemfile. The advantage with this approach is that you can also configure the archive to setup external dependencies like any other deb or rpm package. One of my recent projects came up with a in house solution. Now there are tools like pkgr
You can download a standalone RVM package here: https://github.com/wayneeseguin/rvm/tags
You can reference the RVM installer script for details on what an RVM install does. Simply replace the network calls with references to some local file, and you should be good to go.
That said, once RVM is installed, I'm not sure if it'll let you do an offline Ruby install easily, but this should get you started.
Well you need to download the source code from somewhere to install RVM, Rails. Not very clear as to how your Prod environment lacks an internet connection. Could you please give more details?

Rails keeps telling me that it's not currently installed

I use rvm to manage different rubies and their gemsets. My shell is zsh with oh-my-zsh configured with basic settings. Enabled oh-my-zsh plugins are ruby, rails, osx, and git. Here's the command I used to install ruby-1.8.7 and rails-3.0.7.
rvm install 1.8.7
rvm use 1.8.7
gem install rails -v=3.0.7
and then I typed rails and got:
Rails is not currently installed on this system. To get the latest version, simply type:
$ sudo gem install rails
You can then rerun your "rails" command.
I've tried more thorough installs also, Like reinstall rubygems after switching to ruby-1.8.7, or create a completely new gemset, but with no luck.
Here's the rvm info:
ruby-1.8.7-p352#rails:
system:
uname: "Darwin yicai.local 10.8.0 Darwin Kernel Version 10.8.0: Tue Jun 7 16:32:41 PDT 2011; root:xnu-1504.15.3~1/RELEASE_X86_64 x86_64"
bash: "/bin/bash => GNU bash, version 3.2.48(1)-release (x86_64-apple-darwin10.0)"
zsh: "/bin/zsh => zsh 4.3.9 (i386-apple-darwin10.0)"
rvm:
version: "rvm 1.8.6 by Wayne E. Seguin (wayneeseguin#gmail.com) [https://rvm.beginrescueend.com/]"
ruby:
interpreter: "ruby"
version: "1.8.7"
date: "2011-06-30"
platform: "i686-darwin10.8.0"
patchlevel: "2011-06-30 patchlevel 352"
full_version: "ruby 1.8.7 (2011-06-30 patchlevel 352) [i686-darwin10.8.0]"
homes:
gem: "/Users/nil/.rvm/gems/ruby-1.8.7-p352#rails"
ruby: "/Users/nil/.rvm/rubies/ruby-1.8.7-p352"
binaries:
ruby: "/Users/nil/.rvm/rubies/ruby-1.8.7-p352/bin/ruby"
irb: "/Users/nil/.rvm/rubies/ruby-1.8.7-p352/bin/irb"
gem: "/Users/nil/.rvm/rubies/ruby-1.8.7-p352/bin/gem"
rake: "/Users/nil/.rvm/bin/rake"
environment:
PATH: "/Users/nil/.rvm/gems/ruby-1.8.7-p352#rails/bin:/Users/nil/.rvm/gems/ruby-1.8.7-p352#global/bin:/Users/nil/.rvm/rubies/ruby-1.8.7-p352/bin:/Users/nil/.rvm/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/sbin"
GEM_HOME: "/Users/nil/.rvm/gems/ruby-1.8.7-p352#rails"
GEM_PATH: "/Users/nil/.rvm/gems/ruby-1.8.7-p352#rails:/Users/nil/.rvm/gems/ruby-1.8.7-p352#global"
MY_RUBY_HOME: "/Users/nil/.rvm/rubies/ruby-1.8.7-p352"
IRBRC: "/Users/nil/.rvm/rubies/ruby-1.8.7-p352/.irbrc"
RUBYOPT: ""
gemset: "rails"
and the gem version is 1.8.10, the latest.
If you're running a rails command immediately after installing rails, you will need to restart your terminal before your commands will be recognized.
I had this problem today. Not completely related to your question, but since this page is what comes up in Google when I search for "Rails is not currently installed on this system", I thought I would add my answer:
What happened is that I was using ruby 1.9.2 with rails for a while, but then I needed to use ruby 1.8.7 to run some other script that I found.
Afterwards, I wanted to change by system back to using 1.9.2, and that's where the problem started:
$ rvm list
=> ruby-1.8.7-p352 [ x86_64 ]
ruby-1.9.2-p290 [ x86_64 ]
$ rvm use 1.9.2
I thought that would do the trick. But no, that gives me the "Rails is not currently installed on this system" message.
What I had forgotten is that I had configured rails using an rvm gemset. So I needed to specify the correct gemset when I was selecting which ruby version to make active.
$ rvm gemset list_all
gemsets for ruby-1.8.7-p352 (found in /Users/asgeo1/.rvm/gems/ruby-1.8.7-p352)
global
gemsets for ruby-1.9.2-p290 (found in /Users/asgeo1/.rvm/gems/ruby-1.9.2-p290)
global
rails31
$ rvm use ruby-1.9.2-p290#rails31
That did the trick.
Mac OS X, rbenv, and rails
I was getting the exact same issue but with rbenv rather than rvm. After verifying a correct .bash_profile.
.bash_profile
export PATH="$HOME/.rbenv/bin:/usr/local/bin:$PATH"
eval "$(rbenv init -)"
Restart the shell
exec $SHELL -l
Check the path
echo $PATH
Finally
I repeatedly installed and uninstalled rails but it was never placed in the .rbenv/bin directory after rbenv rehash. In the end I did a find . -name rails and uninstalled every gem that was returned and uninstalled rails. Then:
$ gem install rails
$ rbenv rehash
$ which rails
/Users/palmerc/.rbenv/shims/rails
I had the same issue and found that RVM was not showing as installed either if I tried the rvm command. All it took to fix both problems was running this command in the terminal
$ source ~/.rvm/scripts/rvm
Restart your terminal and then re-run your rails command
Rails is not reporting that it isn't installed. Your Debian system is telling you that rails isn't installed. One thing about rvm is that it relies on some complicated bash shell scripting and you sometimes need to start a fresh shell for changes to appear. You should also make sure that the correct rvm shell commands were added to your .zshrc file.
Also check your path to make sure the ~/.rvm/gems/... path in included.
I ran into this issue using rbenv. Turns out gem install rails did in fact install Rails but rails was not recognized as an executable. The fix for me was to run rbenv rehash.
I found this fix and more details on setting up Rails 5 at https://gorails.com/setup/osx/10.11-el-capitan
I have encountered this problem, but it has been resolved.
I use macOS, I do not use rvm, I only use HomeBrew, I first use gem env to get the installation directory of all gems, mine is:
$ gem env
RubyGems Environment:
   -RUBYGEMS VERSION: 3.1.2
   -RUBY VERSION: 2.7.1 (2020-03-31 patchlevel 83) [x86_64-darwin19]
   -INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/2.7.0
   -USER INSTALLATION DIRECTORY: /Users/myname/.gem/ruby/2.7.0
...
Then you try to go to /usr/local/lib/ruby/gems/2.7.0 to find the executable file directory of the rails gem that you have installed, for example: /usr/local/lib/ruby/gems/2.7.0/bin, then add to the path environment variable
I found this problem but the solutions above didn't solve it. I am not using rvm (and I'm working on mac) and I had to update the path to add rails executable directory:
echo 'export PATH="/usr/local/lib/ruby/gems/3.0.0/bin:$PATH"' >> ~/.zshrc
I had a similar issue, but with rbenv.
I originally installed ruby on bash. Then I played around with .bashrc in VIM, messed that file up, and reset it back to default. In doing so, I unknowingly removed the exported rbenv $PATH. Because of this, my terminal no longer recognized that I had ruby installed.
I revisited the ruby installation page (https://gorails.com/setup/ubuntu/15.04) and tried to set up my rbenv path again with this command:
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
It failed.
Luckily, I had already switched to zsh (with oh-my-zsh) between the time I messed up my .bashrc and the time I tried to access irb from my terminal.
My solution was to set up the rbenv path per the installation guide, but by replacing all instances of .bashrc with .zshrc like so:
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
Hope this helps!
Here's what I've done. And the problem is gone. Hence I guess problem solved.
rvm use system
change to the system ruby. remove all gems in it using the command provided and explained here. then I install wanted ruby versions from scratch:
rvm install 1.8.7
rvm install rails -v 3.0.7
then bundle install
for further detail, might need dig into the gem install procedure.
add source ~/.rvm/scripts/rvm to your .bashrc file if rails installs fine but then you get the error "rails is not currently installed". This frustrated me for a while but I found the answer here: http://www.codelearn.org/blog/how-to-install-ruby-rails-screencasts-linux-mac-windows
I just reloaded my terminal
source ~/.bashrc
See: How do I reload .bashrc without logging out and back in?
Rbenv users
I had the same issue and this worked for me.
Setting the ruby version in the current directory.
rbenv local 2.7.1
Then I was able to run rails new
I had the same problem but the solution above didn't help.
This was my scenario
rvm list
=> ree-1.8.7-2012.02 [ i686 ]
ruby-1.9.3-p125 [ x86_64 ]
which ruby
/Users/dev/.rvm/rubies/ree-1.8.7-2012.02/bin/ruby
which rails
/usr/bin/rails
gem list --local
..
rails (3.2.8)
rails2_asset_pipeline (0.1.20)
railties (3.2.8)
..
rvm use ruby-1.9.3-p125
which ruby
/Users/dev/.rvm/rubies/ruby-1.9.3-p125/bin/ruby
which rails
/Users/dev/.rvm/gems/ruby-1.9.3-p125/bin/rails
By uninstalling rails and railties and reinstalling rails when using ree my problem was resolved.
Hope this helps others in my situation, not sure how I got into it :S
I had the same problem, I ended up deleting my .rvmrc rvm --create --rvmrc 1.8.7#project where the 1.8.7#project is whatever you want your ruby to be. cded in and out and it worked. http://sirupsen.com/get-started-right-with-rvm/
Just had same problem and couldn't find an answer. Here's what I did:
find current rails path
$ which rails
returns something like this: /usr/local/rails
Delete current version:
$ sudo rm -rf /usr/local/rails
Reinstall rails
$ sudo gem install rails
I ran into this same issue and none of the answers given helped so I thought I'd share my solution in case it might be useful for someone else.
I was messing around with my .profile and .bashrc files and along the way I messed up my RVM install. Still not sure exactly what I did, but the fix was easy. Just had to run the following command, which cleans up all of your system path settings for RVM:
rvm get [head|stable] --auto-dotfiles
Note that if you're running an old version of RVM this may upgrade your setup, which may not be what you want.
A possible solution is to not maintain two different configuration files .bash_profile and .bashrc
The solution as suggested in this excellent post on the difference between .bash_profile and .bashrc is to source .bashrc from your .bash_profile file, then putting PATH and common settings in .bashrc.
Quoting,
add the following lines to .bash_profile:
if [ -f ~/.bashrc ]; then
source ~/.bashrc
fi
end quote
I had this error after updating ruby. I had to run 'bundle install' to fix it.
Try to specify gemset explicitely in your Gemfile:
source 'https://rubygems.org'
ruby "2.2.3"
#ruby-gemset=rails424
Try This:
You need to change your terminal emulator preferences to allow login shell.
Sometimes it is required to use /bin/bash --login as the command.
$ bin/bash --login
$ rails -v
I had this message on my Mac:
Rails is not currently installed on this system. To get the latest
version, simply type:
and it was about the $PATH not being correct. The system has an outdated version of rails (/usr/bin/ruby). The path to your chosen version of ruby ($HOME/.rbenv/versions/2.3.0/bin) must precede the system's outdated version along $PATH var, like below:
export PATH="$HOME/.rbenv/versions/2.3.0/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:$PATH"
adjust it to your version of ruby.
For MacOS (High Sierra):
Tokaido is the Rails installer system recommended on the "Getting Started" Rails guide page for Mac OS. But it doesn't just install, it runs its own shell scripts. If you start out using that, which sources its own shell environment, then later start a terminal without launching from the Tokaido shell, this happens, because the "rails" command falls back to the original system rails code on the Mac.
For mine, the 'which rails' command in a normal terminal returns
/usr/bin/rails
But after launching Tokaido's shell, 'which rails' gives this path:
/Users/charlesross/.tokaido/Gems/2.2.0/bin/rails
Out of nowhere Rails wasn't currently installed but, what fixed it was
rvm use ruby-2.6.0
...and verified my path in .bash_profile
export PATH="$PATH:$HOME/.rvm/bin"
I was having this problem today. I haven't 100% solved it, but in new tabs I can do rvm use 2.5.5 and then rails -v works fine.
➜ my-repo git:(next_release) ruby -v
ruby 2.5.5p157 (2019-03-15 revision 67260) [x86_64-darwin18]
➜ my-repo git:(next_release) rails -v
Rails is not currently installed on this system. To get the latest version, simply type:
$ sudo gem install rails
You can then rerun your "rails" command.
➜ my-repo git:(next_release) rvm use 2.5.5
Using /Users/amberwilkie/.rvm/gems/ruby-2.5.5
➜ my-repo git:(next_release) rails -v
Could not find rake-12.3.3 in any of the sources
Run `bundle install` to install missing gems.
➜ my-repo git:(next_release) bundle install
I was looking through the source and found another error message that suggested the user run the following command.
I ran the command and everything now works. None of the suggestions above worked for me. Run the command from inside your newly created Rails app.
gem pristine --all
Here is how it worked for me:
Intall rvm in mac by following the mac installation instruction
rvm install ruby
gem install rails
rails --version
For me ( MacOS Monterey, rbenv) adding rails version to gem install command get the problem resolved.
you can find a specific version of rails that matches to your ruby from this link and replace the VERSION .
gem install rails -v VERSION
rbenv rehash
after successful installation, then rails should be added to /Users/your_user/.rbenv/shims
Also plz check that your shims directory should be the first element of your path.
➜ ~ echo $PATH #
/Users/ario/.rbenv/shims: ...
I was following along with the Odin Project ruby-on-rails course by
installing rbenv,
adding eval "$(rbenv init -)" to ~/.zshrc
installing rails gem
attempting to run rails new my_first_rails_app
But I had forgot to run source ~/.zshrc after editing the file, so I was seeing the error:
Rails is not currently installed on this system.

RVM finding system gems' executables

I have installed RVM along with ruby versions. However if I fire up the console and run the command rails server, bundle install, etc. I get this error
bash: /usr/bin/rails: /usr/bin/ruby1.8: bad interpreter: No such file or directory
But if I run rvm use 1.9.2 first, then everything is ok. I tried using `rvm use --default 1.9.2' but nothing changed. Does this mean it uses a different ruby from the ones in RVM? Thanks in advance!
Explanation of rubygems bin folders and PATH
Oh. You didn't have rails installed in your rvm ruby, but you did in your system ruby.
Individual gems, like rails can have a bin directory that will contain executable helper scripts. Your system default rubygems is making symlinks from your system /usr/bin/ dir into the gem's bin folder for these helper executables.
RVM provides a similar facility, except instead of polluting the system /usr/bin dir, it just appends its ~/.rvm/gems/#{rvm_gemset_string}/bin folder to the PATH environment variable.
Importing system Rubygems list into your new rvm rubies' gem directories
RVM by default will not import your gems from your system ruby installation into your rvm ruby installs. It makes a full clean fork of the entire ruby system including rubygems (the gem 'rubygems') and rubygems' gem list. When you rvm install 1.9.2 it's like you've made a completely new install of everything used with ruby.
If you'd like to get all your system ruby gems that you were previously using into your preferred rvm ruby, try this:
rvm use system
rvm gemset export system.gems
rvm use 1.9.2
rvm gemset import system.gems
#You'll now have all your system gems reinstalled to your new ruby version
Original Answer/ Edits from #Telemachus
Try moving the lines that source rvm to the end of your ~/.bash_profile or ~/.bashrc (whichever you have it in):
'[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function'
.
bash: /usr/bin/rails: /usr/bin/ruby1.8: bad interpreter: No such file ...
| | ^--------------------------------\
^ Bash, not rvm; ^/usr/bin/rails, not ~/.rvm/gems/*/bin/rails; |
Some ruby leftover from a previous install in the os
You have rails installed in /usr/bin, which is probably before the rvm ruby bin path in your bash echo $PATH variable, so it's finding the system rails install (/usr/bin/rails, a ruby script) which starts like this:
#! /usr/bin/ruby18
You've gotta make the conflict stop happening, the best of all possible ways is making sure that RVM's bin dir is at the beginning of your PATH. This happens in the #Load rvm environment script that you added to your ~/.bash_profile when installing rvm. If you installed rvm as a system library rather than just for your user, this will be different.
If you get to that case, ask #Telemachus.
You'll then need to ensure you've gotten the rails gem installed in your new rvm ruby as above.
Acceptance Test:
You'll find that when you've done rvm use 1.9.2, then which ruby will return something like ~/.rvm/rubies/1.9.2/bin/ruby, and which rails should return something like ~/.rvm/gems/*/bin/rails.
I just solved the same problem on Windows Vista.
My console was giving me this message:
$ rails -v
sh: /c/RailsInstaller/Ruby1.9.2/bin/rails: C:/Projects/railsinstaller/Stage/Ruby1.9.2 /bin/ruby.exe: bad interpreter: No such file or directory
I just edited the first line of this file:
C:\RailsInstaller\Ruby1.9.2\bin\rails
And made it point to the correct location for ruby.exe, on my system, like this:
#!C:\RailsInstaller\Ruby1.9.2\bin\ruby.exe
Et voilà, problem solved!
You need to run rvm use --default 1.9.2, not just rvm use --default.

How to completely wipe rubygems along with rails etc

Ok, so I decided I'd be cool and try to use Rails3 that's in beta. Then, things were getting hard to manage so I got rvm. I installed ruby 1.9.2-head in rvm and things were working, and then a computer restart later rails wouldn't start up. So I figured I'd just try running the system ruby and start rails in it. same error. Then, I uninstalled rails3 and got rails: no such file or directory type errors..
So now I'm royally screwed because rails2 is still installed but will not uninstall because of invisible dependencies, along with a lot of other random gems. How do I completely clear out all ruby gems and such so I can start anew?
I've recently had to so just this. I had built up alot of cruft with my system installed ruby and gems and wanted to clean all that out and move everything over to run under rvm for various projects.
1. Clean up old and busted
First thing I did, before messing with rvm (or run rvm system to get back to the system ruby), was to remove all my gems:
gem list | cut -d" " -f1 | xargs gem uninstall -aIx
WARNING: this will uninstall all ruby gems. If you installed as root you may want to switch to root and run this.
2. Install new hotness
Now you can run gem list to see what is left.
Time to install rvm, I recomend blowing away your current install and reinstall fresh:
rm -rf $HOME/.rvm
bash < <( curl http://rvm.beginrescueend.com/releases/rvm-install-head )
Now the real trick is to use gemsets to install rails 3, and this is easy if you follow Waynee Seguin's gist:
rvm update --head
rvm install 1.8.7
rvm --create use 1.8.7#rails3
curl -L http://rvm.beginrescueend.com/gemsets/rails3b3.gems -o rails3b3.gems
rvm gemset import rails3b3.gems
One difference is I use 1.8.7 since I have had issues with 1.9.2-head and RSpec, but 1.8.7 has been smooth.
You say that you already got Rails 2 and afterwards installed rvm. Try if you can remove Ruby and Rails using the package manager of your system (yum, apt, ...)
The error you got is most likely the result a link in some general place which still exists, but is pointing to the real installation directory which no longer exists.
For example: /usr/bin/ruby exists and is pointing to /usr/local/lib/ruby/1.9.2/bin/ruby which no longer exists.
Afterwards manually clean out any Ruby and Rails related paths in /usr and its subdirectories.

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