How do I fix the You don t have write permissions into the usr bin directory error when installing Rails

Question

I m trying to install Rails 3 on a brand new MacBook Pro running OS X 10 6 3  Ruby 1 8 7  and Rails 2 3 5 and I m wondering if I ve hosed myself   So far  I ve run these commands     gem update --system   gem install arel tzinfo builder memcache-client rack rack-test rack-mount erubis mail text-format thor bundler i18n   gem install rails --pre   However  when I run the last command  I get this error   ERROR   While executing gem      Gem  FilePermissionError      You don t have write permissions into the  usr bin directory    I think it wants me to run the command with sudo so that it can write over  usr bin rails   But if I do that  won t I be overwriting my Rails 2 3 5 executable   I don t want to do that   Instead  I d like to keep both versions of Rails   How do I do that

User · Answer

sudo gem install cocoapods --pre -n  usr local bin   This works for me

User · Answer

Using the -n  usr local bin flag does work  BUT I had to come back to this page every time I wanted to update a package again  So I figured out a permanent fix for this    For those interested in fixing this permanently   Create a    gemrc file  vim  gemrc   With the following content    gemdir     -    gem ruby install  -n  usr local bin   Now you can run your command normally without the -n flag   Enjoy

User · Answer

You can use sudo gem install -n  usr local bin cocoapods  This works for me

User · Answer

For me  something different worked  that I found in on this answer from a similar question  Probably won t help OP  but maybe someone like me that had a similar problem   You should indeed use rvm  but as no one explained to you how to do this without rvm  here you go   sudo gem install tzinfo builder memcache-client rack rack-test rack-mount     abstract erubis activesupport mime-types mail text-hyphen text-format       thor i18n rake bundler arel railties rails --prerelease --force

User · Answer

To fix your specific error you need to run that command as sudo  ie   sudo gem install rails --pre

User · Answer

This Error hit me after installing RVM correctly  Solution  re-boot Terminal   Reference RailsCast s RVM Install tutorial

User · Answer

On macOS High Sierra  this solved my issue   sudo gem update --system -n  usr local bin gem

User · Answer

use -n parameter to install like for cocoapods   sudo gem install cocoapods -n  usr local bin

User · Answer

I d suggest using RVM it allows you have multiple versions of Ruby Rails installed with gem profiles and basically keep all your gems contained from one another  You may want to check out a similar post How can I install Ruby on Rails 3 on OSX

[ruby-on-rails-3] How do I fix the "You don't have write permissions into the /usr/bin directory" error when installing Rails?

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