Updating multiple local working copies using a single GitHub source?
Switching to GitHub and can't seem to find information on how to do something I used to do with SVN:

First of al I'm a tester so I never commit changes, but I do need to keep a number of local copies of the project each with a small difference to the trunk - staging, production, decreased timer values etc

I used to use CornerStone on Mac (just fwiw/don't have it any more), and a single update from SVN would update all my various local 'dependent projects' (all of them the same, apart from one or two lines, usually in a config file). I'd review the inevitable conflicts and almost always reject them, provided the only difference in the conflicting file was my customisation for test purposes, or if there was something new I'd merge it in and leave my staging environment URLs or whatever as they were.

Can I do this sort of thing efficiently with GitHub? (preferably using GitHub's or some other Mac GUI client?) 

I did look at the documentation, but can't seem to find anything on this so any help much appreciated/maybe it's kind of unusual to be pulling changes to lots of almost-identical local projects and always be rejecting certain conflicts.. :)
Updating multiple local working copies using a single GitHub source?
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Switching to GitHub and can't seem to find information on how to do something I used to do with SVN:

First of al I'm a tester so I never commit changes, but I do need to keep a number of local copies of the project each with a small difference to the trunk - staging, production, decreased timer values etc

I used to use CornerStone on Mac (just fwiw/don't have it any more), and a single update from SVN would update all my various local 'dependent projects' (all of them the same, apart from one or two lines, usually in a config file). I'd review the inevitable conflicts and almost always reject them, provided the only difference in the conflicting file was my customisation for test purposes, or if there was something new I'd merge it in and leave my staging environment URLs or whatever as they were.

Can I do this sort of thing efficiently with GitHub? (preferably using GitHub's or some other Mac GUI client?) 

I did look at the documentation, but can't seem to find anything on this so any help much appreciated/maybe it's kind of unusual to be pulling changes to lots of almost-identical local projects and always be rejecting certain conflicts.. :)