Install Clang on Ubuuntu LTS

bionic.sh

#!/bin/bash

# Install Clang 8 on Ubuuntu 18.04.2 LTS

# Turn on errexit.
set -e

# You do not need to add new repository to the source list since the
# llvm toolchain now can be found on the bionic bionic-updates
# universe repositories.

# Install the main components.
sudo apt install clang-8 lldb-8 lld-8 clang-tools-8

# Create symbolic links.
cd /usr/bin/
for i in clang{,++,-cpp}-8; do
    sudo ln -sf $i ${i::-2}
done
for i in lld{,-link}-8; do
    sudo ln -sf $i ${i::-2}
done
sudo ln -sf ld.lld-8 ld.lld
for i in lldb{,-argdumper,-mi,-server}-8; do
    sudo ln -sf $i ${i::-2}
done

# Set the default compiler cc to clang using alternatives mechanism.
sudo update-alternatives \
     --install /usr/bin/cc cc /usr/bin/clang 30 \
     --slave /usr/share/man/man1/cc.1.gz cc.1.gz /usr/share/man/man1/clang-8.1.gz

xenial.sh

#!/bin/bash

# Install Clang 5 on Ubuuntu 16.04.3 LTS

# Turn on errexit.
set -e

# Add the llvm repository to the source list.
sudo tee /etc/apt/sources.list.d/llvm-toolchain-xenial.list <<HERE
deb http://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main
# deb-src http://apt.llvm.org/xenial/ llvm-toolchain-xenial-5.0 main
HERE

# Add the llvm key to the list of trusted keys.
wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -

# Resynchronize the package index from sources.
sudo apt update

# Install the main components.
sudo apt install clang-5.0 lldb-5.0 lld-5.0 clang-tools-5.0

# Create symbolic links.
cd /usr/bin/
for i in clang{,++,-cpp}-5.0; do
    sudo ln -s $i ${i::-4}
done
for i in lld{,-link}-5.0; do
    sudo ln -s $i ${i::-4}
done
sudo ln -s ld.lld-5.0 ld.lld
for i in lldb{,-argdumper,-mi,-server}-5.0; do
    sudo ln -s $i ${i::-4}
done

# Set the default compiler cc to clang using alternatives mechanism.
sudo update-alternatives \
     --install /usr/bin/cc cc /usr/bin/clang 10 \
     --slave /usr/share/man/man1/cc.1.gz cc.1.gz /usr/share/man/man1/clang-5.0.1.gz