build_ruby_env_on_mac.sh

#!/usr/bin/env bash

set -eu

RUBY_VERSION="2.1.2"

if ! which -s brew; then
    echo "[ERROR] Homebrew is required."
    exit 1
fi

if ! which -s rbenv; then
    brew install rbenv ruby-build
    echo "[INFO] Write a definition below in the bashrc or the zshrc, for loading rbenv."
    echo "eval \"\$(rbenv init -)\""
fi

eval "$(rbenv init -)"

if [ $(rbenv versions | grep -c "^\** ${RUBY_VERSION} ") -eq 0 ]; then
    echo "[INFO] Change the version of readline to 6.2.4."
    if [[ $(brew versions readline | grep -c "^6.2.4") -eq 0 ]]; then
        echo "[INFO] Install the version 6.2.4 of readline."
        cd /usr/local/
        git checkout 0181c8a Library/Formula/readline.rb
        brew install readline
    else
        brew switch readline 6.2.4
    fi

    echo "[INFO] Install ruby and set the version in global."
    rbenv install ${RUBY_VERSION}
    rbenv global ${RUBY_VERSION}
fi

if ! which -s gem; then
    echo "[ERROR] gem command is required."
    exit 1
fi

echo "[INFO] Install basical gems."
cat <<EOF | xargs gem install
bundler
pry
EOF