Install protobuf 3.3 on Ubuntu 16.04

# Make sure you grab the latest version
curl -OL https://github.com/google/protobuf/releases/download/v3.3.0/protoc-3.3.0-linux-x86_64.zip

# Unzip
unzip protoc-3.3.0-linux-x86_64.zip -d protoc3

# Move protoc to /usr/local/bin/
sudo mv protoc3/bin/* /usr/local/bin/

# Move protoc3/include to /usr/local/include/
sudo mv protoc3/include/* /usr/local/include/

# Optional: change owner
sudo chown $USER /usr/local/bin/protoc
sudo chown -R $USER /usr/local/include/google

In my install (ubuntu 16.04 from an nvidia-docker container) the protoc actually being used was in /usr/bin, not /usr/local/bin, so
cp protoc3/bin/* /usr/bin
was necessary - for whatever reason, which protoc led to /usr/local/bin but the actual one being used was in /usr/bin

++ Getting the following error after using the above steps:

$ protoc --version
-bash: /usr/local/bin/protoc: cannot execute binary file: Exec format error