You don't have write permissions for the /var/

问题:

I have ruby installed on my ubuntu 16.04.

$which ruby  

/usr/bin/ruby

$ruby -v 

ruby 2.3.0p0 (2015-12-25) [x86_64-linux-gnu]

$gem install bundler 

ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /var/lib/gems/2.3.0 directory.

Any help will be greatly appreciated!

回答1:

You first need to uninstall the ruby installed by Ubuntu with something like sudo apt-get remove ruby.

Then reinstall ruby using rbenv and ruby-build according to their docs:

cd $HOME
sudo apt-get update 
sudo apt-get install git-core curl zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev python-software-properties libffi-dev

git clone https://github.com/rbenv/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL

rbenv install 2.3.1
rbenv global 2.3.1
ruby -v

The last step is to install Bundler:

gem install bundler
rbenv rehash

Then enjoy!

Derek

回答2:

If you want to use the distribution Ruby instead of rb-env/rvm, you can set up a GEM_HOME for your current user. Start by creating a directory to store the Ruby gems for your user:

$ mkdir ~/.ruby

Then update your shell to use that directory for GEM_HOME and to update your PATH variable to include the Ruby gem bin directory.

$ echo 'export GEM_HOME=~/.ruby' >> ~/.bashrc
$ echo 'export PATH="$PATH:~/.ruby/bin"' >> ~/.bashrc
$ source ~/.bashrc

(That last line will load the settings directly into your current shell.)

Now you should be able to install Ruby gems under your user using the gem command. I was able to get this working with Ruby 2.5.1 under Ubuntu 18.04. If you are using a shell that is not Bash, then you will need to edit the startup script for that shell instead of bashrc.

回答3:

Try using chown -R on the var/lib/gems directory, assigning ownership to the user [rubyusername] in this example, the user that will be installing and developing with gems.

 # chown -R rubyusername:rubyusername /var/lib/gems 

This recursively changes everything under the gems directory. For extra security on multi-user systems, you can also create a group, rather than chowning the individual rubyusername, and add users to that group.

回答4:

Rather than changing owners, which might lock out other local users, or –some day– your own ruby server/deployment-things... running under a different user...

I would rather simply extend rights of that particular folder to... well, everybody:

cd /var/lib
sudo chmod -R a+w gems/

(I did encounter your error as well. So this is fairly verified.)

回答5:

Building on derek's answer above, it is generally not recommended to use the system provided Ruby instance for your own development work, as system tools might depend on the particular version or location of the Ruby install. Similar to this answer for Mac OSX, you will want to follow derek's instructions on using something like rbenv (RVM is a similar alternative) to install your own Ruby instance.

However, there is no need to uninstall the system version of Ruby, the rbenv installation instructions provide a mechanism to make sure that the instance of Ruby available in your shell is the rbenv instance, not the system instance. This is the

echo 'eval "$(rbenv init -)"' >> ~/.bashrc

line in derek's answer.