A Bash script to install Ruby on the Raspberry Pi

install_ruby_rpi.sh

#!/bin/bash

# --------------------------------------------------------------------------------------------
# Installs Ruby using rbenv/ruby-build on the Raspberry Pi (Raspbian)
#
# Run from the web:
#   bash <(curl -s https://gist.githubusercontent.com/blacktm/8302741/raw/install_ruby_rpi.sh)
# --------------------------------------------------------------------------------------------

# Set the Ruby version you want to install
RUBY_VERSION=3.3.0

# Welcome message
echo -e "
This will install Ruby using rbenv/ruby-build.

It will take about 2 hours to compile on the original Raspberry Pi,
35 minutes on the second generation, and 16 minutes on the third.\n"

# Prompt to continue
read -p "  Continue? (y/n) " ans
if [[ $ans != "y" ]]; then
  echo -e "\nQuitting...\n"
  exit
fi
echo

# Time the install process
START_TIME=$SECONDS

# Check out rbenv into ~/.rbenv
git clone https://github.com/rbenv/rbenv.git ~/.rbenv

# Add ~/.rbenv/bin to $PATH, enable shims and autocompletion
read -d '' String <<"EOF"
# rbenv
export PATH="$HOME/.rbenv/bin:$PATH"
eval "$(rbenv init -)"
EOF

# Save to ~/.bashrc
echo -e "\n${String}" >> ~/.bashrc

# Enable rbenv for current shell
eval "${String}"

# Install ruby-build as an rbenv plugin, adds `rbenv install` command
git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build

# Install dependencies
#  See: https://github.com/rbenv/ruby-build/wiki#suggested-build-environment
sudo apt update
sudo apt install -y autoconf bison build-essential libssl-dev libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev libffi-dev libgdbm6 libgdbm-dev libdb-dev

# Install Ruby, don't generate RDoc to save lots of time
CONFIGURE_OPTS="--disable-install-doc --enable-shared" rbenv install $RUBY_VERSION --verbose

# Set Ruby as the global default
rbenv global $RUBY_VERSION

# Don't install docs for gems (saves lots of time)
echo "gem: --no-document" > ~/.gemrc

# Reminder to reload the shell
echo -e "\nReload the current shell to get access to rbenv using:"
echo "  source ~/.bashrc"

# Print the time elapsed
ELAPSED_TIME=$(($SECONDS - $START_TIME))
echo -e "\nFinished in $(($ELAPSED_TIME/60/60)) hr, $(($ELAPSED_TIME/60%60)) min, and $(($ELAPSED_TIME%60)) sec\n"

Calculate total time compilation.

total_time() {
  local T=$1
  local H=$((T/60/60%24))
  local M=$((T/60%60))
  local S=$((T%60))
  printf '\nFinished in '
  [[ $H -gt 0 ]] && printf '%d hours ' $H
  [[ $M -gt 0 ]] && printf '%d minutes ' $M
  [[ $D -gt 0 || $H -gt 0 || $M -gt 0 ]] && printf 'and '
  printf '%d seconds\n' $S
}

total_time $SECONDS

tnk u
SET RUBY VIA ARGV OR FALLBACK TO DEFAULT

Set the default Ruby version

DEFAULT_RUBY_VERSION=3.3.0

Set the Ruby version from command-line argument or fallback to default

RUBY_VERSION=${1:-$DEFAULT_RUBY_VERSION}