问题
I'm on Ubuntu. I type in sudo gem install rails. This works fine, installs railes and 7 other gems fine. Yet $ rails blog is saying this:
The program 'rails' is currently not installed. You can install it by typing:
sudo apt-get install rails
回答1:
how did you install rubygems, as an admin, or as a user? if you installed it as a user, it may not have the bin directory in your path.
If I were you, (assuming you installed rubygems into your home folder), I would trash that installation dir (not sure where it defaults to, maybe ~/rubygems? or ~/.rubygems?), then run setup.rb from the rubygems tarball as admin (through sudo) I've done this at least a dozen times on ubuntu, and haven't run into the issue you are hitting.
If that isn't the case, could you please link to the blog post you were following?
回答2:
Type
gem env
It will give you the installable directory where the bins of the gems are being installed. Something like this:
EXECUTABLE DIRECTORY: /usr/bin
Make sure this directory is in your path.
回答3:
Make sure your gem executable path is added to your system path so that the system can find the rails executable.
回答4:
I know this is an old thread but the same error had me stuck. Make sure you add
source ~/.rvm/scripts/rvm to your .bashrc file
来源：https://stackoverflow.com/questions/3065839/sudo-gem-install-rails-this-doesnt-give-me-a-rails-command-for-bash