For the system we need to install three main applications on Ubuntu. And for the configuration you need to install some lib packages also.
1. Apache
2. Subversion
3. Trac
4. Python

Install SVN

sudo apt-get install apache2
sudo apt-get install subversion
sudo apt-get install libapache2-svn

Check If SVN Installed or not

If everything finished successfully with any warning or error you can check the installation. Type “svnadmin –version” on terminal. If installation was success you will get the output something like shown below.

mittu@tutorboy:~$ svnadmin --version
svnadmin, version 1.6.5 (r38866)
 compiled Aug 31 2009, 18:42:02

Copyright (C) 2000-2009 CollabNet.
Subversion is open source software, see http://subversion.tigris.org/
This product includes software developed by CollabNet (http://www.Collab.Net/).

The following repository back-end (FS) modules are available:

* fs_base : Module for working with a Berkeley DB repository.
* fs_fs : Module for working with a plain file (FSFS) repository.

Install Trac

sudo apt-get install libapache2-mod-python
sudo apt-get install python-setuptools
sudo apt-get install python-subversion

sudo easy_install Trac

Check If Trac Installed or not

Type the ” trac-admin ?” on the terminal,If installation was success you will get the output something like shown below.

mittu@tutorboy:~$ trac-admin ?
Welcome to trac-admin 0.11.7rc1
Interactive Trac administration console.
Copyright (c) 2003-2009 Edgewall Software

Type:  '?' or 'help' for help on commands.

Trac [/home/mittu/?]>

Configuration & Example Project creation.

See Part 3 – How to Configure SVN Trac on Ubuntu.