The following assumes that you have read all the User Documents on the Project Documentation page and that you have completed all the steps described on the Download, Installation, and Usage page.
Currently the OSPC-ACA project history is in a Fossil repository. Before cloning a local copy of this repository, you need to install Fossil on your computer.
Cloning the OSPC-ACA repository (repo) on your computer is a better way of getting the project source code than downloading either a Tarball or ZIP archive as described in the User Documents. A cloned repo contains the full history of the source code --- rather than just a single version of the code --- so that you can see how changes have been made in the past. Having a cloned repo on your computer also will increase your productivity in using the PTC calculator and allows you to consider contributing your enhancements to the open source project.
Installing Fossil
Fossil is a free, open-source distributed software configuration management system described here. Installing Fossil involves downloading a single executable file to your computer and putting it in a directory that is on your PATH. The latest versions of Fossil for Windows, Mac, and Linux, are available here and the "Fossil Quick Start" document is available here. Test your Fossil installation by changing to any directory other than the one in which you put the Fossil executable and then entering the following command at the operating system prompt:
<any-dir-not-containing-fossil-executable>$ fossil version
If the installation has been successful, Fossil will write to the screen a message something like this:
This is fossil version 1.32 [6c40678e91] 2015-03-14 13:20:34 UTC
Cloning the OSPC-ACA Repository
Before cloning the OSPC-ACA repo, you must decide what to call the single file containing the repo and the directory location for that local repo file. We strongly suggest navigating to your home directory (which is denoted by the ~ symbol below) and executing the following commands:
~$ mkdir fossil-repos
~$ cd fossil-repos
fossil-repos$ fossil clone
https://www.chiselapp.com/user/mrh/repository/OSPC-ACA/
OSPC-ACA.fossil
fossil-repos$ cd ..
The last of these command leaves you in your home directory.
Checking Out a Local Source-Code Tree
To get a copy of the source code out of the local repo that you just created, execute the following commands (if you are on Windows, you must, of course, use the backslash character \ instead of what is shown below) from your home directory:
~$ fossil open ../fossil-repos/OSPC-ACA.fossil
This command will create a source-code tree --- with the tree's root directory being ~/OSPC-ACA --- that contains the latest version of the project source code.
Now you can browse the source code with any editor, but more interestingly you can review the history of the project contained in the Fossil repository. To see the project's development timeline, execute the following commands:
~$ cd OSPC-ACA
OSPC-ACA$ fossil ui
Continue reading about how use Fossil to record changes you make in the project source code here.