This has been tested on Raspbian
apt-get install -y libssl-dev ncurses-dev
wget http://www.erlang.org/download/otp_src_19.2.tar.gz
wget -q -O - https://raw.githubusercontent.com/techgaun/extract/master/extract >> ~/.bashrc # I already had [this](https://github.com/techgaun/extract)
extract otp_src_19.2.tar.gz
cd otp_src_19.2
./configure
make
make install
cd /opt
wget "https://github.com/elixir-lang/elixir/releases/download/v1.4.0/Precompiled.zip"
mkdir elixir && mv Precompiled.zip elixir/ && cd elixir
extract Precompiled.zip
echo "export PATH=\$PATH:/opt/elixir/bin" > /etc/profile.d/elixir.sh
chmod +x /etc/profile.d/elixir.sh
source /etc/profile.d/elixir.sh
# or add to ~/.bashrc