Build Software

GNU Build System

Download the python interpreter

We need to download the latest version of the python interpreter. Which is located at.

Python Download Page

We want version 3.5.1. On the 3.5.1 download page, we choose the ‘Gzipped source tarball’. It’s important to note that this is a ‘Source release’, which is often the version you need for Linux operating systems (Ubuntu, Red Hat).

python download page

Unpackage the source directory

$ tar xzvf Python-3.5.1.tgz
$ cd Python-3.5.1
$ ls

Doc      LICENSE  Makefile.pre.in  Objects  Parser    README      config.guess  configure.ac   setup.py
Grammar  Lib      Misc             PC       Programs  Tools       config.sub    install-sh
Include  Mac      Modules          PCbuild  Python    aclocal.m4  configure     pyconfig.h.in

GNU build steps

The GNU build system is broken into three distinct steps.

1. Configure
2. Build
3. Install

The configure step sets up all of the file dependencies for the package on your system. This is the basis of portable software. If the configure step completes successfully, the Build and Install steps should always work.

Configure

There will be a number of directories and files. The main file we are interested in is the configure script. This will setup the compile time dependencies. The script can take numerous options.

$ ./configure --help

You may notice a large number of options. If you don’t know what these options do; then you do not need to be concerned with them. The general rule, is that the default (configure with no options) is perfectly appropriate for the majority of use cases.

We are intertested in the --prefix option, however. As a segment of the help message dictates.

By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc.  You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.

Without superuser privileges, you will not be able to install the package in /usr/local. Additionally, the /usr directory tends to be a system package, and it is almost never a good idea to put packages in there.

So let’s configure the build to install in a subdirectory python2 in our home directory.

$ ./configure --prefix=$HOME/python3

python configure output

Build

Notice the directory now has a Makefile in it

$ ls

Doc      LICENSE  Makefile         Misc     PC       Programs  Tools         config.log     configure     
Grammar  Lib      Makefile.pre     Modules  PCbuild  Python    aclocal.m4    config.status  configure.ac  
Include  Mac      Makefile.pre.in  Objects  Parser   README    config.guess  config.sub     install-sh

The generated Makefile is what contains all of the compiling commands with correct dependences. The make command, will interpret and execute the Makefile.

$ make

A bunch of compiling commands, will almost always see warnings; usually can be ignored.

Install

$ make install

A bunch of install commands coupled with rm and cp.

$ cd $HOME/python3
$ ls

bin  include  lib  share

Test our installation

$ cd bin
$ ./python3

Python 3.5.1 (default, Jun  8 2016, 11:23:55) [GCC 6.1.1 20160501] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 

To quit the python interpreter type quit() at the prompt and press enter. Notice that the version in the header matches the version we just installed.
However, the problem with this install is that it is not available for use without an absolute path.

$ python3

bash: python3: command not found