Determine Ruby Version from Within Rails

Determine ruby version from within Rails

Use this global constant:

RUBY_VERSION

Other relevant global constants include:

RUBY_PATCHLEVEL
RUBY_PLATFORM
RUBY_RELEASE_DATE

Usage example via irb session:

irb(main):001:0> RUBY_VERSION
=> "1.8.7"

How to find out which rails version an existing rails application is built on?

rake gems will print out what gems, dependencies, and versions are installed, frozen, etc.

If you are using bundler than you can use bundle show to list all the gems that your app is using.

Rails 5: How Do I Find Out Which Gem Depends on a Specific Ruby Version?

Your case seems like not a gem dependencies, but like you have ruby version definition somewhere in your apps code.

Check this files under your projects root folders:

• .rvmrc
• .ruby-version
• .ruby-gemset
• .versions.conf

And also check your Gemfiles for string ruby-2.5.2.

How to find out which Ruby version an existing Rails project is based on?

If no version-specific gems are in use, I'm not sure it's possible to determine the exact ruby version used during development. In any case, the app may work fine against several versions, depending on the features it has.

If the app has comprehensive tests, you could just work back to find the latest version for which all the tests pass.

Checking the minimum version of Ruby compatible with the Rails version used would also help to narrow the field.

Rails: How does the console decide which Ruby version to use?

Since RUBY_VERSION returns 2.1.1 you are using Ruby 2.1.1. Probably irb prompt is patched in some way that returns 2.1.0 instead of 2.1.1, I guess by RVM. It should be patched, since standard irb prompt should be something like

irb(main):001:0>

Which ruby version am I using?

If ruby -v shows 2.6.3, then you are using the ruby which ships with the system by default. You can confirm this in several ways. Running the shell command which ruby will show /usr/bin/ruby. Checking your PATH will show /usr/bin earlier than the location of the homebrew or rbenv installations.

If you wish to run one of the others, you can put it earlier on the PATH or invoke it explicitly by giving the fully qualified name such as /usr/local/opt/ruby/bin/ruby myscript.rb. Another alternative which avoids twiddling the PATH variable is to use a shebang line at the beginning of different scripts pointing explicitly to the version to use with that script.

---

Related Topics