Installs antlr4 on linux

install_antlr4.sh

#!/bin/bash

export ANTLR4_JAR=antlr-4.7-complete.jar

if ! type -p java; then

  # Install Java 8
  echo "Installing Java 8"
  sudo add-apt-repository ppa:webupd8team/java
  sudo apt updatee; sudo apt install oracle-java8-installer
  
  # Check version 
  javac -version

fi


if ! -f "${ANTLR4_JAR}"; then

# Download Runtime
echo "Downloading ${ANTLR4_JAR}"
  wget http://www.antlr.org/download/${ANTLR4_JAR}

  sudo mkdir -p /opt/antlr/bin

  sudo mv antlr-4.7-complete.jar /opt/antlr
fi

echo "Writing antlr4 script to /opt/antlr4/bin"

cat > /opt/antlr/bin/antlr4 << EOF
#!/bin/bash
java -jar /opt/antlr/${ANTLR4_JAR} \$@
EOF
chmod +x /opt/antlr/bin/antlr4


if ! grep -Fxq "#TAG_ANTLR4" ~/.bashrc; then

echo "Writing ~/.antlr4rc"

cat > /home/$USER/.antlr4rc << EOF
export PATH=/opt/antlr/bin:\$PATH
export CLASSPATH=".:/opt/antlr/${ANTLR4_JAR}:\$CLASSPATH"
alias grun='java org.antlr.v4.runtime.misc.TestRig'
EOF

echo "Appending to ~/.bashrc"
echo '#TAG_ANTLR4' >> ~/.bashrc
echo 'source /home/$USER/.antlr4rc' >> ~/.bashrc

fi