If you'd like to hack on Singular, you can follow the instructions provided by github and start by forking the Sources repo on GitHub:

See here for a brief description of the git-supported development model we use.

For help with this procedure and general questions about development please write to libsingular-devel@googlegroups.com. Feel free to ask for comments or a review of your changes on the mailing list as well.

Before sending a pull request to merge your changes, make sure that

any new functions are properly documented
new functions are tested
- consider special cases! Optimally all decision branches of new functions should be covered by tests
the Singular test suite passes without failure. [Instructions on running the test suite](Running-test) is available on this wiki.

Note: Almost everything GitHub-related can be done from command-line with the following tool http://hub.github.com.