undoing something

["John Dlugosz" <JDlugosz@TradeStation.com>]

I made a mistake.  Big deal, now that I know that git storage is
immutable and changes just add to what's already there.  

A quick look at
	git reflog show topic
tells me that {1} is the one I want.  So, how do I rewind branch topic
to point to topic@{1} ?
I did it by making a tag, and then in gitk pointing to it and picking
"reset to here" from the context menu.  

A while back I was looking for the right/easy way to simply repoint my
branch to where I wanted.  The best answer was to use push.  But, I
wonder if gitk and other high-level commands simply call a more
primitive command that does this?  And can I call it directly?  Or is
push with a dot as the repository just doing this with no excessive
processing and trust that the side-effects are all vacuous?

--John
(please excuse the footer; it's not my choice)

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