Ruby tries to load from gem from older version - ruby

Question

I'm trying to run an script that calls the ansi gem with the following line:
require 'ansi/code'
However, when I try running it, I get the following error:
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- ansi/code (LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from ./taoup:4:in `<main>'
I tried to make sure I run Ruby v2.6.5 and reinstalled the dependencies afterward.
→ rbenv versions
system
2.1.3
2.2.1
* 2.6.5 (set by /Users/ricky/.rbenv/version)
→ gem install ansi
Successfully installed ansi-1.5.0
Parsing documentation for ansi-1.5.0
Done installing documentation for ansi after 0 seconds
1 gem installed
For reference, it seems that rubygems is running at v.2.6.5.
→ gem env
RubyGems Environment:
- RUBYGEMS VERSION: 3.0.3
- RUBY VERSION: 2.6.5 (2019-10-01 patchlevel 114) [x86_64-darwin18]
- INSTALLATION DIRECTORY: /Users/ricky/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0
- USER INSTALLATION DIRECTORY: /Users/ricky/.gem/ruby/2.6.0
- RUBY EXECUTABLE: /Users/ricky/.rbenv/versions/2.6.5/bin/ruby
- GIT EXECUTABLE: /usr/local/bin/git
- EXECUTABLE DIRECTORY: /Users/ricky/.rbenv/versions/2.6.5/bin
- SPEC CACHE DIRECTORY: /Users/ricky/.gem/specs
- SYSTEM CONFIGURATION DIRECTORY: /Users/ricky/.rbenv/versions/2.6.5/etc
- RUBYGEMS PLATFORMS:
- ruby
- x86_64-darwin-18
- GEM PATHS:
- /Users/ricky/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0
- /Users/ricky/.gem/ruby/2.6.0
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- "install" => "--no-rdoc --no-ri"
- "update" => "--no-rdoc --no-ri"
- REMOTE SOURCES:
- https://rubygems.org/
I think I need to direct the execution environment to use my intended version of Ruby.

Answer 1

Okay, looks like the script was pointing to a specific installation of Ruby, as specified here:
#!/usr/bin/ruby
This version of ruby was not the one I intended to run on. It is a different version afterall:
→ /usr/bin/ruby --version
ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin18]
So I made a quick and dirty fix on the script by rewriting the Shebang declaration like this:
#!/Users/ricky/.rbenv/versions/2.6.5/bin/ruby
If anyone knows a version-agnostic way to fix this dependency, please let me know!