In [ ]:

    

!which root


    

In [ ]:

    

TCanvas c;TH1F h("h","ROOT Histo;X;Y",64,-4,4); h.FillRandom("gaus"); h.Draw(); c.Draw();


    

In [ ]:

    

TFile f("o2sim_pythia8hi_N10_TGeant3_HitsITS.root"); auto t=(TTree*)f.Get("o2sim");
 if(t) {  auto br=t->GetBranch("ITSHit");
 std::vector<o2::itsmft::Hit> *hits = nullptr;
 br->SetAddress(&hits);
 br->GetEntry(0);
 std::cerr << "Found " << hits->size() << "hits" << std::endl; } else { std::cerr << " no tree "; }