Open your terminal and run

curl -sSL https://raw.githubusercontent.com/rvm/rvm/master/binscripts/rvm-installer | bash -s stable

For the rvm command to work, you need to run:

source ~/.rvm/scripts/rvm

Now, run rvm list known

This shows the list of versions of the Ruby interpreter.

Now, run rvm install ruby@latest to get the latest Ruby version.

If you type ruby -v in the terminal, you should see ruby X.X.X.

If it still shows you ruby 2.0., run rvm use ruby-X.X.X --default.

Prerequisites for Windows 10:

• C compiler. You can use http://www.mingw.org/
• make command available otherwise it will complain that "bash: make: command not found". You can install it by running mingw-get install msys-make
• Add "C:\MinGW\msys\1.0\bin" and "C:\MinGW\bin" to your path environment variable

The command sudo in

sudo echo 'export PATH="/opt/homebrew/bin:$PATH"' >> ~/.zshrc

is applied to echo and not to >> ~/.zshrc. Below is one possible way to do what you want.

sudo zsh -c "cat >> ~/.zshrc" <<< 'export PATH="/opt/homebrew/bin:$PATH"'

However, when you entered

echo 'export PATH="/opt/homebrew/bin:$PATH"' >> ~/.zshrc

you should not have received an error, unless you are not the owner of ~/.zshrc. You probably can fix this by entering the following.

sudo chown $USER ~/.zshrc
echo 'export PATH="/opt/homebrew/bin:$PATH"' >> ~/.zshrc