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Installing a new Ruby with rbenv on Mac OS

Install a new Ruby with rbenv on Mac OS (and make yourself a superhero)

If you're doing stuff with Ruby on a Mac, e.g. installling Jekyll or something, by default you'll end up having to use the sudo command to do stuff, since the permission to modify the default config is not available to your user account.

This sucks and should be avoided. Here's how to fix that.

Installing a new Ruby

To make this better, we are going install a new, custom Ruby. This used to be a big, scary thing, but thanks to the awesome tools Homebrew and rbenv, it's a snap.*

A word of warning: you will have to use Terminal to install this stuff. If you are uncomfortable with text, words, and doing stuff with your computer beyond pointing and hoping, this may not work well for you. But if that's the case, I'm not sure why you were trying to use Ruby in the first place.

First, install Homebrew

Homebrew (or just brew, since that's the name of the command you'll use), is a package manager for Mac OS. It makes installing all sorts of cool tools easy.

Open terminal and command your Mac to do your bidding with the following command:

$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

This little bit of magic will download the Homebrew install script and walk you through the install process. It's not too scary, and should only take a couple of minutes. Accept all defaults.

Once that's done, your system will be all set up to use Homebrew, and its superhappyfuncommand, brew. Let's try it out by installing a helpful little utility, tree.

$ brew install tree

Once you do that, run the tree utility like this:

$ tree

You should get a pretty ASCII picture of your current directory structure.

Once you have Homebrew, your powers are much greater and you can install all sorts of stuff without ever having to invoke sudo or mess with permissions. And you'll have harnessed the work of thousands of developers who are working in caves and darkend alcoves crafting Homebrew install packages just for you.

Second, install rbenv and a new Ruby

Ok, Homebrew is installed and you now have some new super powers. Let's use them to get you a new Ruby. We'll start by installing rbenv and it's ruby-build plugin. rbenv is a Ruby version manager that lets you change with Ruby you're currently using, and ruby-build helps you install a custom Ruby. Seriously, when you're done with this, you'll be like some sort of new X-Men team member, with the mutant power to install new Rubies with a thought.

Let's start by installing the tools:

$ brew install rbenv ruby-build

Assuming that all went to plan, you have just upgraded yourself and your Mac. But you can't quite use your new capabilities yet. You need to hook up rbenv so it can do some stuff. If you want to know what that stuff is, good for you! Go read the documentation. For now, here's what you need to do:

WARNING: If you use a shell other than bash, like zsh, you'll need a slightly different command set up the rbenv environment stuff. If you don't know what I'm talking about, you're probably fine. If you do, then you can figure this out on your own.

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

To make this apply to your current Terminal session, do this:

$ source ~/.bash_profile

Now it's time to install a new Ruby. We'll choose a fairly modern version of the 1.9 family of Rubies. It's not as shiny as the newer Ruby 2.0 stuff, but it's more familiar to most folks, like your favorite pair of socks. Or something

$ rbenv install 1.9.3-p547

That'll take a few minutes. Once it's done, you have a shiny new toy. But to play with it, you need to do a couple of other things. First, make the new Ruby the default for your system:

$ rbenv global 1.9.3-p547

After that, you should install the most useful too for Ruby, Bundler. I am asking you to do this not because it's required, but because I care deeply and profoundly about you. Really, I do.

$ gem install bundler

I did ask you to install Bundler because of my need to ensure your wellbeing. I also did it to demontrate that, if all went well, you've accomplised the task this little guide was supposed to help you do, installing a new Ruby on your Mac that you have control over, a Ruby sans sudo.

Please enjoy your new Ruby responsibly.

Learning more

Like Spider-Man, you have now been granted great power. And with great power comes the need to read some documentation.

Really, if you want to leverage Homebrew and rbenv–and you really should want to–go read their documentation. You'll learn how to find new things to install and other interesting facts, like why Unicorns vomit rainbows.

Ok, maybe you won't learn anything about that last bit. But you'll be able to do more with the expensive hunk of processed sand on your desk.

Good luck. And ping me on Twitter (@stonehippo) if you need help, or if something here doesn't work. I wrote this in a few minutes to help out Andy Clarke, and I am may have missed something, so beware and all that.


*Ok, maybe not a snap. But it won't hurt too bad.

@marctorrellas

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marctorrellas commented May 31, 2018

Thanks!

@AlwinaO

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AlwinaO commented Jun 9, 2018

This was very helpful. Thank you!!

@benmort

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benmort commented Jun 26, 2018

cheers

@ZhuofuChen

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ZhuofuChen commented Aug 30, 2018

Cheers!

@sydsrirak

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sydsrirak commented Oct 9, 2018

Wicked, thanks very much!

@rubyphull

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rubyphull commented Oct 16, 2018

hi - I am installing Ruby following https://www.theodinproject.com/courses/web-development-101/lessons/your-first-rails-application

after running -
curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash

I see -
Checking for rbenv shims in PATH: not found --> how can I fix this?

@ashwinimanoj

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ashwinimanoj commented Dec 10, 2018

Thanks a lot!

@agness

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agness commented Dec 17, 2018

The homebrew install command should be updated to

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Otherwise this is still the best resource around. Thanks for making.

@camiloquezada89

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camiloquezada89 commented Dec 24, 2018

I need your help guys!

rbenv: version ruby-2.5.3' is not installed (set by /Users/camiloquezadamaris/Documents/Cursos/rubyOnRails/blog/.ruby-version)`

@iammike

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iammike commented Feb 1, 2019

The homebrew install command should be updated to

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

Otherwise this is still the best resource around. Thanks for making.

ping! @stonehippo

@acarbonellb

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acarbonellb commented Feb 12, 2019

Nice one, thank you.

@vahotm

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vahotm commented Feb 22, 2019

ruby-build is now dependency for rbenv and installed automatically

@mishaberrien

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mishaberrien commented Apr 19, 2019

Amazing. THANKS!

@edwardbattistini

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edwardbattistini commented Jul 10, 2019

Such a great step by step tutorial ! Love the superhero references !!
Now that bash is going to be replaced by zsh would it be possible to have a tuto with those commands ? Or is there already one ?
Thanks

@stonehippo

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stonehippo commented Oct 23, 2019

@edwardbattistini yes, I’ll update this once I switch over to Catalina and zsh.

@stonehippo

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stonehippo commented Oct 23, 2019

FYI, I’ve updated the Homebrew install script above to the latest version. I’ll probably do some other stuff to modernize this, too, as soon as I get a chance. (Thanks for the reminder, @iammike).

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