How to update an ubuntu 12.x box to protoc 2.5.0 and so build Apache hadoop 2.x+

Here are some working notes on how to push up an Ubuntu 12.x machine to a version of protoc that builds Hadoop. It is a shame that protobuf.jar doesn't include a protoc compiler
Actually it's also a shame that protobuf.jar isn't backwards compatible across versions. I'm
now ooking at Apache Thrift and thinking "maybe I should adopt that in my own code".


Run these as root:

cd ~
apt-get -y remove protobuf-compiler
curl -# -O https://protobuf.googlecode.com/files/protobuf-2.5.0.tar.gz
gunzip protobuf-2.5.0.tar.gz 
tar -xvf protobuf-2.5.0.tar 
cd protobuf-2.5.0
./configure --prefix=/usr
make
make install
protoc --version

Then log in as you and again run

protoc --version

The output of the --version commands must be "libprotoc 2.5.0". Any error; any different version: your build of Hadoop won't.