Find successor of common ancestor

Hi folks,


suppose the following situation:

I've forked some branch A into B, now A and B have evolved 
independently for quite some time into A' and B'. Now I'd like
to rebase B' along A' history line step by step - first on A+1, 
then A+3, ... until A' (that's what I'd call zip-rebase).

For this I need to find out the successor commit A (along the A'
history line). Does anyone know how to do that ?


cu
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 Enrico Weigelt, metux IT service -- http://www.metux.de/

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