Install old ruby on MacBook Pro m1/m2 chip using rbenv(Fresh installation)

Installing older ruby prior to 2.7.2 does not work easily on Mac m1/m2 chips. I wasted a lot of time in this.

I will share the steps which worked for me and it might save others time as well.

Make a fresh installation. First uninstall homebrew(brew) and rbenv and remove all the configurations settings that you might have done while trying to install ruby.

You might have homebrew in /opt/homebrew or in some other places like if you enabled rosetta mode.

Make sure to remove all the configurations settings as well in .bash_profile, .zprofile, .zshrc and lets start with a fresh installation.

 Here are the steps that you need to follow:

1) Enable Rosetta mode(This installs all the application using arch -x86_64):

Go to Applications => Utilities from finder.

Select Terminal.

Press CMD+I (capital i) for "Get Info" or right click on go to in

Check box for "Open using Rosetta"

You will be asked to install Rosetta, install it and restart your Mac.

2) Install homebrew using this command:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

And follow the instructions in the end to configure homebrew.

Run cat .zprofile and make sure you have this:

eval "$(/usr/local/bin/brew shellenv)"

3) Install rbenv using this command:

brew install rbenv

And configure rbenv so that it loads on start.

Add this to .zshrc:

eval "$(rbenv init - zsh)"

4) Finally, Install ruby using this command(Restart your Mac and make sure brew and rbenv commands are working):

CFLAGS="-Wno-error=implicit-function-declaration" rbenv install 2.1.7

These are the steps which worked for me.