Install Ruby

A current Ruby with gem and Bundler, separate from any Ruby your system came with.

Install Ruby
Terminal
```
brew install ruby
```
Use it instead of the old system Ruby
Terminal
```
echo 'export PATH="/opt/homebrew/opt/ruby/bin:$PATH"' >> ~/.zshrc
source ~/.zshrc
echo "export PATH=\"$(gem environment gemdir)/bin:\$PATH\"" >> ~/.zshrc
source ~/.zshrc
```
macOS ships an outdated Ruby you shouldn't install gems into. The last two lines also put commands from installed gems (like rails) on your PATH.

Check it worked

Check the versions
Terminal
```
ruby -v && gem -v && which ruby
```
which ruby should show a path under /opt/homebrew.

Undo it

Uninstall Ruby
Terminal
```
brew uninstall ruby
```

Install RubyNeeds sudo
Terminal · Ubuntu / Debian
```
sudo apt install -y ruby-full
```

Install gems in your home folder (no sudo needed)

Terminal · Ubuntu / Debian

echo 'export GEM_HOME="$HOME/gems"' >> ~/.bashrc
echo 'export PATH="$HOME/gems/bin:$PATH"' >> ~/.bashrc
source ~/.bashrc

Check it worked

Check the versions
Terminal · Ubuntu / Debian
```
ruby -v && gem -v
```

Undo it

Uninstall RubyNeeds sudo
Terminal · Ubuntu / Debian
```
sudo apt remove -y ruby-full
```

Install Ruby with the DevKit
PowerShell
```
winget install RubyInstallerTeam.RubyWithDevKit.3.4
```
The DevKit lets gems that need compiling install properly. Close and reopen PowerShell afterwards.
Finish the DevKit setup
PowerShell
```
ridk install
```
Press Enter to pick the default option.

Check it worked

Check the versions
PowerShell
```
ruby -v; gem -v
```

Undo it

Uninstall Ruby

PowerShell

winget uninstall RubyInstallerTeam.RubyWithDevKit.3.4