Ruby version management (rbenv, rvm) - Step-by-Step Execution

Concept Flow - Ruby version management (rbenv, rvm)

Install rbenv or rvm

↓

Initialize environment

↓

List available Ruby versions

↓

Install chosen Ruby version

↓

Set global or local Ruby version

↓

Use Ruby version in shell

↓

Run Ruby programs with selected version

This flow shows how you install and use rbenv or rvm to manage Ruby versions step-by-step.

Execution Sample

Ruby

rbenv install 3.1.2
rbenv global 3.1.2
ruby -v

This code installs Ruby 3.1.2, sets it as the global version, then shows the Ruby version in use.

Execution Table

Step	Command	Action	Result/Output
1	rbenv install 3.1.2	Downloads and installs Ruby 3.1.2	Ruby 3.1.2 installed
2	rbenv global 3.1.2	Sets Ruby 3.1.2 as global version	Global Ruby version set to 3.1.2
3	ruby -v	Checks current Ruby version	ruby 3.1.2p0 (output depends on exact patch)
4	exit	End of commands	Execution stops

💡 All commands executed; Ruby version 3.1.2 is active globally

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
Ruby version installed	none	3.1.2 installed	3.1.2 installed	3.1.2 installed	3.1.2 installed
Global Ruby version	default system Ruby	default system Ruby	3.1.2	3.1.2	3.1.2
Current Ruby version (ruby -v)	default system Ruby	default system Ruby	3.1.2	3.1.2	3.1.2

Key Moments - 3 Insights

Why does 'ruby -v' show the system Ruby version before setting global version?

Before running 'rbenv global 3.1.2', the shell uses the default system Ruby. The execution_table row 3 shows the version after setting global version.

What happens if you install a Ruby version but don't set it as global or local?

The installed Ruby version is available but not used by default. The shell continues using the previous Ruby version until you set it, as shown between steps 1 and 2.

How does rbenv or rvm know which Ruby version to use?

They modify environment variables and shims so that when you run 'ruby', the selected version runs. This is reflected in the change of 'Global Ruby version' in variable_tracker after step 2.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output of 'ruby -v' at step 3?

A ruby 3.1.2p0

B ruby 2.7.0

C Command not found

D ruby 3.0.0

💡 Hint

Check the 'Result/Output' column for step 3 in execution_table.

At which step is the global Ruby version set to 3.1.2?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Look at the 'Action' column in execution_table to find when global version changes.

If you skip 'rbenv global 3.1.2', what Ruby version will 'ruby -v' show at step 3?

A 3.1.2

B System default Ruby

C No Ruby version

D Error message

💡 Hint

Refer to variable_tracker for 'Global Ruby version' before step 2.

Concept Snapshot

Ruby version management lets you install and switch Ruby versions easily.
Use rbenv or rvm to install versions.
Set global or local version to choose which Ruby runs.
Check with 'ruby -v' to confirm active version.
This helps run different projects with different Ruby versions.

Full Transcript

This visual trace shows how Ruby version managers like rbenv or rvm work step-by-step. First, you install a Ruby version using a command like 'rbenv install 3.1.2'. Then you set that version as the global default with 'rbenv global 3.1.2'. Finally, running 'ruby -v' shows the active Ruby version, confirming the switch. Variables track the installed Ruby versions and which one is active globally. Key moments clarify why the Ruby version changes only after setting global version and how the environment is configured. The quiz tests understanding of these steps and outputs. This helps beginners see how Ruby version management commands affect the environment and Ruby version used.