How to Manage Ruby Versions with RVM (with examples)

Ruby Version Manager (RVM) is a command-line tool that simplifies the complex process of managing multiple Ruby environments on a single machine. Whether you are a seasoned developer or a newcomer to Ruby, RVM allows you to seamlessly switch between Ruby versions and manage gem dependencies across different projects. This flexibility makes it a vital tool for anyone working extensively with Ruby, allowing you to maintain various Rails applications that may each require different Ruby versions. The following examples illustrate how RVM can be utilized for various tasks related to Ruby management.

Install One or More Versions of Ruby

Code:

rvm install 2.7.0 3.0.0

Motivation: Often in development, you may need to use different Ruby versions for different projects, especially if maintaining legacy code while transitioning to newer versions. Installing multiple Ruby versions ensures compatibility and smooth operation across projects.

Explanation:

• rvm install: The command to instruct RVM to install Ruby.
• 2.7.0 3.0.0: The specific versions of Ruby that you want to install. You can list as many versions as needed, separated by spaces.

Example Output:

Installing Ruby from source to: /usr/local/rvm/rubies/ruby-2.7.0
...
Installation of Ruby 2.7.0 is complete.
Installing Ruby from source to: /usr/local/rvm/rubies/ruby-3.0.0
...
Installation of Ruby 3.0.0 is complete.

Display a List of Installed Versions

Code:

rvm list

Motivation: Knowing which Ruby versions are currently installed on your system helps you manage your development environment effectively, allowing you to decide which version to use for a particular project.

Explanation:

• rvm list: This command lists all the Ruby versions that have been installed using RVM on your system.

Example Output:

rvm rubies
   ruby-2.7.0 [ x86_64 ]
   ruby-3.0.0 [ x86_64 ]

# => - current
# =* - current && default
#  * - default

Use a Specific Version of Ruby

Code:

rvm use 3.0.0

Motivation: While working on a project that requires a specific Ruby version, you must switch to that version to avoid compatibility issues, such as deprecated features or gem mismatches.

Explanation:

• rvm use: This command is used to specify which Ruby version to switch to for the current session.
• 3.0.0: The version you wish to use.

Example Output:

Using /usr/local/rvm/gems/ruby-3.0.0

Set the Default Ruby Version

Code:

rvm --default use 3.0.0

Motivation: If you consistently use a particular Ruby version across most of your projects, setting it as the default version saves time by eliminating the need to manually switch Ruby versions every time you begin a new terminal session.

Explanation:

• rvm --default use: This command sets the specified Ruby version as the default version to be used whenever a new shell session is started.
• 3.0.0: The version you want as the default.

Example Output:

Using /usr/local/rvm/gems/ruby-3.0.0

Upgrade a Version of Ruby to a New Version

Code:

rvm upgrade 2.7.0 3.1.0

Motivation: Keeping up with Ruby updates is crucial for benefiting from performance improvements, security enhancements, and new features. Upgrading Ruby can ensure that your applications run smoother and more securely.

Explanation:

• rvm upgrade: The command to upgrade an existing Ruby version to a newer one.
• 2.7.0: The current version of Ruby you have installed.
• 3.1.0: The new version of Ruby you wish to upgrade to.

Example Output:

Migrating gemsets from ruby-2.7.0 to ruby-3.1.0
Installing Ruby from source to: /usr/local/rvm/rubies/ruby-3.1.0
...
Migration complete for 2.7.0 to 3.1.0.

Uninstall a Version of Ruby and Keep Its Sources

Code:

rvm uninstall 2.7.0

Motivation: Over time, you may want to remove an older Ruby version to free up space or because it is no longer needed. Uninstalling a Ruby version while retaining its source saves space while allowing you to reinstall it easily later on if needed.

Explanation:

• rvm uninstall: This command is used to remove an installed Ruby version.
• 2.7.0: Specifies the version of Ruby you wish to uninstall.

Example Output:

ruby-2.7.0 - #remove
Removing Ruby 2.7.0 ...

Remove a Version of Ruby and Its Sources

Code:

rvm remove 2.7.0

Motivation: Completely removing a Ruby version, including all of its sources, is useful if the version is outdated or you are certain that your projects will no longer depend on it, thus freeing up more disk space.

Explanation:

• rvm remove: Similar to uninstall, but also deletes the source files associated with the Ruby version.
• 2.7.0: Indicates the Ruby version to be entirely removed from the system.

Example Output:

ruby-2.7.0 - #remove
Removing Ruby and source files for 2.7.0 ...

Show Specific Dependencies for Your OS

Code:

rvm requirements

Motivation: Different versions of Ruby may have different dependencies. Understanding what is required by your operating system to install and effectively use a specific Ruby version helps in avoiding installation errors.

Explanation:

• rvm requirements: This command displays the dependencies and requirements that must be fulfilled for rvm to function and for compiling Ruby versions on your current operating system.

Example Output:

Checking requirements for osx.
Requirements installation successful.

Conclusion

RVM is an essential tool in the Ruby ecosystem that simplifies the management of multiple Ruby environments. The ability to effortlessly install, switch, upgrade, and remove Ruby versions ensures that developers can work efficiently across a myriad of projects each requiring different Ruby setups. Mastering the use of RVM can significantly enhance your productivity and help in keeping your Ruby development streamlined and organized.