In root, after doing TFile* file = TFile::Open(path), do TH1F h = (TH1F) file->Get("name"); Then can do h->Draw(options)

To draw multiple histograms on the same page, open them as above, initialise a canvas, then do canvas->Divide(4, 3) to get a 4 x 3 grid of histograms. Then canvas->cd(n) for the nth histogram in the list of (12). And just call h->SetTitle("title") and h->Draw() as one would before.

-- HamishGordon - 20 Aug 2008