Installing Ruby gems not working with Home Brew

Question

The gems I install via sudo gem install ... can't be executed (I get a command not found). They seem to install into /usr/local/Cellar/ which is Brew's install directory (also, the gems in /Library/Ruby/ don't work either). Is there anything else I need to do to make the gems executable? I'm using ZSH on Mac OS X 10.6 with Ruby v1.8 for the one in Brew.

EDIT: It seems to be working now. I just went out for a few hours and came back to try it again.

Solution 1

Homebrew is nice. However unlike brew and npm, gem does not make aliases in /usr/local/bin automatically.

Solution

I went for a very simple approach (as of March 2020):

# Based on "`brew --prefix ruby`/bin"
export PATH=/usr/local/opt/ruby/bin:$PATH
# Based on "`gem environment gemdir`/bin"
export PATH=/usr/local/lib/ruby/gems/3.0.0/bin:$PATH

Add this to your .bashrc (or .bash_profile, .zshrc, etc.).

That's it! Now all Ruby bins and installed gems will be available from your shell!

In older versions of Homebrew (before 2017), there was a separate package for Ruby 2 called ruby20, for which you'd use the following snippet instead:

export PATH=/usr/local/opt/ruby20/bin:$PATH

This line was the only line needed at the time. But, in Ruby 2.1 the gems got moved to a separate directory. No longer under /usr/local/opt/ruby/bin, but instead at /usr/local/lib/ruby/gems/2.0.0/bin (where "2.0.0" is the last major Ruby version for Gem's purposes).

How it works

Homebrew keeps track of where it installed a package, and maintains a symbolic link for you that points there.

$ brew --prefix ruby
/usr/local/opt/ruby

$ l /usr/local/opt/ruby
/usr/local/opt/ruby@ -> ../Cellar/ruby/2.5.3_1

Effectively, adding /usr/local/opt/ruby to PATH is the same as the following:

export PATH=/usr/local/Cellar/ruby/2.5.3_1/bin:$PATH

Except, this long version hardcodes the currently installed version of Ruby and would stop working next time you upgrade Ruby.

As for Gem, the following command will tell you the exact directory Gem adds new packages to:

$ gem environment gemdir
/usr/local/lib/ruby/gems/2.7.0

Tools

These tools were meant to automatically bridge between Homebrew and Gem:

• josh/brew-gem (no longer exists)
• indirect/brewbygems (unmaintained)

I haven't used these but they might work for you.

Solution 2

brew unlink ruby; brew link ruby might add symlinks to /usr/local/bin/:

$ which sass
$ brew unlink ruby; brew link ruby
Unlinking /usr/local/Cellar/ruby/2.0.0-p0... 20 links removed
Linking /usr/local/Cellar/ruby/2.0.0-p0... 31 symlinks created
$ which sass
/usr/local/bin/sass

brew --prefix ruby is still pretty slow, but you could also just add /usr/local/opt/ruby/bin to the path.

$ time brew --prefix ruby
/usr/local/opt/ruby
0.216
$ time brew --prefix ruby
/usr/local/opt/ruby
0.076
$ stat -f%Y /usr/local/opt/ruby
../Cellar/ruby/2.0.0-p0

Solution 3

I like home brew. There's probably a better way to do this, but if you run:

gem environment

That will print out a nice list of all the relevant paths. Look for the one labeled EXECUTABLE DIRECTORY. That's the one you want to add to your path. In my case that's /usr/local/Cellar/ruby/1.9.3-p362/bin/ruby but I would imagine it would change with newer version of Ruby.

I'm using /bin/bash as my shell, but the process of adding it to your path should be pretty much the name.

I use TextWrangler (via the command line tools) to edit my .profile file. To do that, it's just:

edit ~/.profile

When your done, either close your terminal and open a new one, or run:

source ~/.profile

Solution 4

You can be fine with ruby installed by homebrew too.. You just lack the functionality of custom gemsets with homebrew.

first do:

sudo nano /etc/paths

this will bring up nano editor,

then add the following to the paths:

/usr/local/Cellar/ruby/1.9.3-p194/bin

your version of ruby will probably vary.

Thats it. It should now detect your gems.

Oh, btw, you need to Ctrl+X > y > ENTER to save a file in nano.

Solution 5

Using the info in Timo's answer, I've got this:

PATH=/usr/local/opt/ruby/bin:$PATH
GEMSDIR=$(gem environment gemdir)/bin
PATH=$GEMSDIR:$PATH
export PATH

Works for Homebrew, works for the separate gems directory, and doesn't hardcode a Ruby version.

View more solutions

Comments

[Kris]

Or add PATH=/usr/local/Cellar/ruby/1.9.3-p194/bin:$PATH to your .zshrc/.bashrc file.

[Mat Schaffer]

As Laruent mentioned below $(brew --prefix ruby)/bin would probably be a better alternative.

[Timo Tijhof]

I didn't use that before because brew --prefix used to be quite slow, but I see that has improved. I'll adopt it, thanks!

[Dave Everitt]

I had no problem using Homebrew with gem install ruby then (after using rvm for a few years then abandoning it, but being used to non-system-wide gem installs) just gem install [gemname]. To use the gems, I added /usr/local/opt/ruby/bin to the end of my PATH variable in .bash_profile. Simple, and works for me, as I don't need gemsets or multiple Rubies.

[lhagemann]

This should be the accepted answer. The OP is using homebrew, so an answer solving for the particular use case (when available) is more appropriate than suggesting a different workflow.

[sambehera]

update: I use chruby and ruby-install now.. and no longer need rvm.. I like this much much better!

[adriendenat]

I think this should be export PATH="/usr/local/lib/ruby/gems/2.6.0/bin:$PATH"

[Dan Caseley]

This is awesome! I've used the info you've provided here, and iterated on it to produce a version that doesn't hardcode the version number: stackoverflow.com/a/62674795/399007

[myhd]

This fixed my MacOS Smashing dashboard issues on Mojave. Thank you!

[Adem]

in my case, I had to change GEM_HOME, so instead of having export PATH=/usr/local/lib/ruby/gems/2.7.0/bin:$PATH, I have export GEM_HOME="$HOME/.gem" and export PATH="$GEM_HOME/bin":$PATH

[joeldesante]

Important note for anyone using any version of ruby other than 2.7.0 (ie. ruby 3.0.0 in my case). Make sure you change the export PATH=/usr/local/lib/ruby/gems/2.7.0/bin:$PATH to indicate whatever version of ruby you are using. For example, for ruby 3.0.0 you need to following export PATH=/usr/local/lib/ruby/gems/3.0.0/bin:$PATH.

[Chris McElroy]

Yes! This fixed my question too—thanks so much!