Removing all installed Gems and starting over

gem uninstall -aIx

Uninstalls all gems without prompt.

Options

-a, --[no-]all                   Uninstall all matching versions
-I, --[no-]ignore-dependencies   Ignore dependency requirements while
                                 uninstalling
-x, --[no-]executables           Uninstall applicable executables without
                                 confirmation

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From the RVM support site:

RVM installs everything into ~/.rvm. To remove RVM from your system run 'rm -rf ~/.rvm'. You may have one additional config file in ~/.rvmrc and of course the RVM hook in your bash/zsh startup files.

So, just go to the command line and type rm -rf ~/.rvm

All the installed gems are in the ~/.rvm folders, so doing the above will remove the gems and installed rubies in one go.

Gems you added pre-RVM with the default ruby install can be removed by typing this at the command prompt:

for x in `gem list --no-versions`; do gem uninstall $x -a -x -I; done

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For Windows and Unix copy/paste in command prompt (Ruby 1.9.x).

ruby -e "`gem list`.split(/$/).each { |line| puts `gem uninstall -Iax #{line.split(' ')[0]}` unless line.strip.empty? }"

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using RVM, you could just type...

rvm gemset empty GEMSET

where GEMSET is the gemset which you would like to empty. then...

install bundle

yum install bundler and finally

bundle install

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rvm implode (see cli docs) seems to work - and it even tells you where to look at for leftovers

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This is work for me on Ubuntu 16.04. For me, when I was executing command rails -v it throw errors because of NameError. I have installed 3 version of rails (4.2.0, 4.2.6, 5.0.0.1). I was trying to uninstall unnecessary gem using command gem uninstall rails -v version number but I won't able to, but I find a way to solve this problem. In order to uninstall all gems, you have to loop through all entries in gem list with bash scripting. This method is very inconvenient. Thanks to Rubygems 2.1.0, you now could do it with one command. STEP - 1 Firstly, please make sure you upgrade your Rubygems to 2.1.0 or newer. For this run this command (Incase you are working on an older version. You can check your gem version using this command any one of them gem -v or gem --version) gem update --system gem --version STEP - 2 Run this command in you terminal gem uninstall --all Step - 3 Install gem bundles (it is not necessary I think just for precautions) gem install bundle Step - 4 Install the rails on your system using this command gem install rails -v specific version you want to install you can check the rails version on the official site rails all versions example :- I have installed rails 4.2.6 version, you install as per requirement. gem install rails -v 4.2.6 Step - 5 Finally check the version of installed rails framework application by Using basic command rails -v. It will echoed the current version of rails frameworks. Enjoy :) References

http://ruby-journal.com/how-to-uninstall-all-ruby-gems/ http://guides.rubyonrails.org/v4.1/getting_started.html

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Step 1:

I first kept running into an error that said:

You don't have write permissions for the /usr/bin directory

To get permission, I became a root user with (this is potentially dangerous for reasons beyond my current understanding):

sudo -s

Credit

Step 2:

Then, I kept running into an error that said:

[gem] cannot be uninstalled because it is a default gem

This allowed me to uninstall everything:

for i in `gem list --no-versions`; do gem uninstall -aIx $i; done

Credit

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FWIW, there are some weird cases where gems are installed but not really installed:

This should do the trick reasonably reliably.

gem uninstall -Iax `gem list  | grep default | awk '{print $1}'`

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