> Not builtin anyway

Yes. Its a plugin[1] for bzr.

[1] https://launchpad.net/bzr-bisect

I would suggest trying out bzr as its easy to use and has good integration with launchpad.

The 5-minute tutorial[1] is a good start. You can also look at the quick reference[2], its quite self explanatory.

[1] http://doc.bazaar.canonical.com/bzr.2.1/en/mini-tutorial/ind...

[2] http://doc.bazaar.canonical.com/bzr.2.1/en/quick-reference/i...