Ruby Version Management using rbenv

Excerpt : Easy ruby version switching using rbenv

Setting up rbenv for faster ruby installations and version switching using Ubuntu (Linux).

So, In this guide, we gonna be exploring rbenv for ruby version management. This guide assumes that you are using any Debian or Ubuntu Linux. Currently i am using Ubuntu 20.04 LTS You can check this out by :

$ lsb_release -a`
No LSB modules are available.
 
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.3 LTS
Release:	20.04
Codename:	focal

This will print out your current Linux OS version:

Great! Let’s get started

1. Install rbenv using Package manager (Debian, Ubuntu and their derivatives)

$ sudo apt install rbenv

2. Setup rbenv in your shell

$ rbenv init

This will print the following to the terminal :

Load rbenv automatically by appending the following to ~/.bashrc:

eval "$(rbenv init -)"

Okay let’s do that :

$ nano ~/.bashrc

and add the line “eval “$(rbenv init -)” to the end of file. save it. close it.

Close terminal, Open new terminal, run the command :

$ rbenv
rbenv 1.1.1
 
Usage: rbenv <command> [<args>]
 
Some useful rbenv commands are:
   commands    List all available rbenv commands
   local       Set or show the local application-specific Ruby version
   global      Set or show the global Ruby version
   shell       Set or show the shell-specific Ruby version
   install     Install a Ruby version using ruby-build
   uninstall   Uninstall a specific Ruby version
   rehash      Rehash rbenv shims (run this after installing executables)
   version     Show the current Ruby version and its origin
   versions    List all Ruby versions available to rbenv
   which       Display the full path to an executable
   whence      List all Ruby versions that contain the given executable
 
See `rbenv help <command>' for information on a specific command.
For full documentation, see: <https://github.com/rbenv/rbenv#readme>
 
verify if rbenv is properly setup using this rbenv-doctor script : run the below command :
$ curl -fsSL <https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor> | bash
This prints out :
 
Checking for `rbenv' in PATH: /usr/bin/rbenv
Checking for rbenv shims in PATH: OK
Checking `rbenv install' support: not found
Unless you plan to add Ruby versions manually, you should install ruby-build.
Please refer to <https://github.com/rbenv/ruby-build#installation>
 
Counting installed Ruby versions: none
  There aren't any Ruby versions installed under `/home/accesss/.rbenv/versions'.
  You can install Ruby versions like so: rbenv install   2.4.1
Checking RubyGems settings: OK
Auditing installed plugins: OK

Since it shows in the rbenv install support as not found, Let’s install ruby-build :

Heading over to https://github.com/rbenv/ruby-build#installation

It says we can install it as an rbenv plugin :

let’s run the following commands:

As an rbenv plugin

$ mkdir -p "$(rbenv root)"/plugins
$ git clone <https://github.com/rbenv/ruby-build.git> "$(rbenv root)"/plugins/ruby-build

Ok let’s test it by running our rbenv-doctor script again:

$ curl -fsSL <https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor> | bash
Checking for `rbenv' in PATH: /usr/bin/rbenv
Checking for rbenv shims in PATH: OK
Checking `rbenv install' support: /home/accesss/.rbenv/plugins/ruby-build/bin/rbenv-install (ruby-build 20210928-4-g2b9424d)
Counting installed Ruby versions: none
  There aren't any Ruby versions installed under `/home/accesss/.rbenv/versions'.
  You can install Ruby versions like so: rbenv install   3.0.2
Checking RubyGems settings: OK
Auditing installed plugins: OK

That’s it. Installing rbenv includes ruby-build. Great we now have the ability to install ruby versions using rbenv directly

Installing Ruby Versions:

Now we have the ability to

As an rbenv plugin

$ rbenv install --list                 # lists all available versions of Ruby
$ rbenv install 2.2.0                  # installs a Ruby version 2.2.0 to ~/.rbenv/versions

or shorthands

$ rbenv install -l # lists all available version

For upgrading / uninstalling you can checkout rbenv’s readme https://github.com/rbenv/rbenv

Ref: https://javierjulio.com/rbenv/https://github.com/rbenv/rbenv

Let’s install the latest stable ruby version (v 3.0.2)

$ rbenv install 3.0.2
Downloading ruby-3.0.2.tar.gz...
-> <https://cache.ruby-lang.org/pub/ruby/3.0/ruby-3.0.2.tar.gz>
Installing ruby-3.0.2...
Installed ruby-3.0.2 to /home/accesss/.rbenv/versions/3.0.2
 
Let’s see if it is installed, run the following command, to check the list of installed ruby versions in our system, asterisk * represents the currently active :
 
$ rbenv versions
system (set by /home/accesss/.rbenv/version) 3.0.2
Let’s install one more ruby version (2.5.5), to test switching ! Also since i had a old project that needs to be upgraded from 2.5.5 to 3.0.2, so particularly this version :
 
$ rbenv install 2.5.5
Downloading ruby-2.5.5.tar.bz2...
-> <https://cache.ruby-lang.org/pub/ruby/2.5/ruby-2.5.5.tar.bz2>
Installing ruby-2.5.5...
 
WARNING: ruby-2.5.5 is past its end of life and is now unsupported.
It no longer receives bug fixes or critical security updates.
 
Installed ruby-2.5.5 to /home/accesss/.rbenv/versions/2.5.5

Now if we check our installed versions it should show both the versions :

$ rbenv versions
* system (set by /home/accesss/.rbenv/version)
  2.5.5
  3.0.2

Global Ruby Version Switching :

This will set our ruby version for global use (for any shell) in our system by default :

Sets the global version of Ruby to be used in all shells by writing the version name to the ~/.rbenv/version file. This version can be overridden by a per-project .rbenv-version file, or by setting the RBENV_VERSION environment variable.

$ rbenv global 3.0.2
$ rbenv versions
  system
  2.5.5
* 3.0.2 (set by /home/accesss/.rbenv/version)
 
$ rbenv global
3.0.2

This sets our global environment to use 3.0.2

Switch Ruby version for local projects:

This will set our ruby version for a local (project level/directory basis) in our project, you can add a .ruby-version file and the version in to that file. so that whenever you want to tell rbenv to run that project, it will use the version mentioned in .ruby-version.

Sets a local per-project Ruby version by writing the version name to an .rbenv-version file in the current directory. This version overrides the global, and can be overridden itself by setting the RBENV_VERSION environment variable or with the rbenv shell command.

$ cd /yourproject$ rbenv local 2.5.5

This will setup local project ruby version to 2.5.5, you can check that using:

$ rbenv local
2.5.5
``
If you want to switch to 3.0.2 you can do :
 
```bash
$ rbenv local 3.0.2

Great ! you are all set 🙂 Happy Hacking !