Script to install picrate on raspberrypi

picrate_install.sh

#! /usr/bin/env bash
JRVERSION="9.2.8.0"
MRI_RUBY="2.5.0"
GEM="${HOME}/.gem/ruby/${MRI_RUBY}"
JDK_VERSION="8"

function install_jruby {
    echo "installing jruby please wait"
  if [ ! -f "jruby-dist-${JRVERSION}-bin.tar.gz" ]; then
    wget "https://repo1.maven.org/maven2/org/jruby/jruby-dist/${JRVERSION}/jruby-dist-${JRVERSION}-bin.tar.gz"
  fi
  if [[ "$?" != 0 ]]; then
    echo "JRuby-${JRVERSION} Download failed"
  else
    CWD=$PWD # remember current directory
    cd /opt
    sudo tar xzvf "$CWD/jruby-dist-${JRVERSION}-bin.tar.gz"
    cd "$CWD"
  fi
  sudo update-alternatives --install /usr/bin/jruby jruby /opt/jruby-${JRVERSION}/bin/jruby 100
  sudo update-alternatives --install /usr/bin/jgem jgem /opt/jruby-${JRVERSION}/bin/jgem 100
  sudo update-alternatives --install /usr/bin/jirb jirb /opt/jruby-${JRVERSION}/bin/jirb 100
}

function check_jruby {
  if [ ! -d "/opt/jruby-${JRVERSION}" ]; then
    install_jruby
  else
    echo "jruby ${JRVERSION} already installed"
  fi
}
check_jruby

function set_gem_home {
  mkdir -p ${GEM}
  echo "export JAVA_HOME=\"/usr/lib/java-${JDK_VERSION}-openjdk-armhf\"" >> ~/.profile
  echo "export GEM_HOME=\"\${HOME}/.gem/ruby/${MRI_RUBY}\"" >> ~/.profile
  echo "export GEM_PATH=\"\${HOME}/.gem/ruby/${MRI_RUBY}\"" >> ~/.profile
  echo "export PATH=\"\${PATH}:\${GEM_PATH}/bin\"" >> ~/.profile
  echo "gem: --no-document" >> ~/.gemrc
  source ~/.profile
}

function check_gemhome {
        if [[ ! -d ${GEM} ]]; then
          set_gem_home
        else
          echo "Gem home already set"
        fi
}
check_gemhome

function install_picrate {
  echo "installing examples please wait"
  source "${HOME}/.profile"
  jgem install picrate -v 1.2.1
  picrate -i samples
}
install_picrate