I am the original developer of the command line display management utility, cscreen. The original version targeted OS X on PPC and is quite old. I have, however, received requests for a copy of this in situations where someone is still running an older Mac and either is installing it for the first time or is rebuilding their PPC Mac and wants to replace their original. This link should give you the old PPC version of cscreen.
I have also received requests for an upgraded Intel version of cscreen. I do not have a Retina display so I don’t know how this will behave on such machines, but I have upgraded cscreen and recompiled it for Intel and switched to the new non-deprecated APIs. This link should give you the new Intel version of cscreen.
Naturally if you run into any problems, please let me know.
Updated 2012-11-07: I’ve pushed out a new version of cscreen Intel, adding the -i parameter which allows you to use display ID values in lieu of the index, when selecting a display to operate on. These display ID values come from OS X and are assigned permanently when a display is connected to the system. As a result they persist across reboots as well as when the displays are reordered (for example when making a new display primary). As a result you can script work targeting a specific display ID without worrying about index changes. Also I fixed a bug where running cscreen with only an index selection but no other options could potentially cause a resolution change.
Updated 2012-12-23: Yet another new version of the Intel version, this time making it a Universal binary, set up for both 32 and 64 bit systems. Merry Christmas!