List all the files inside a ROOT file and dump an Histogram or object

dump_root_histogram.cpp

/*
 * List the files inside a ROOT file and print the specific histogram or object.
 * 
 * By Alejandro Santos
 *
 * Build with: g++ dump_root_hist.cpp -Wall -g $(root-config --cflags --glibs)
 * 
 */

#include <iostream>
#include <sstream>
#include <string>
#include <vector>

#include <TROOT.h>
#include <TSystem.h>
#include <TStyle.h>
#include <TFile.h>
#include <TCanvas.h>
#include <TGraph.h>
#include <TGraph2D.h>
#include <TH2F.h>
#include <TTree.h>
#include <TApplication.h>
#include <TKey.h>

using namespace std;

void loopdir(TDirectoryFile* f1, string indent = "") {
    TIter next(f1->GetListOfKeys());
    TKey *key;
    while ((key = (TKey*)next())) {
        cout << indent << key->GetName() << endl;
        TClass *cl = gROOT->GetClass(key->GetClassName());
        if (!cl->InheritsFrom("TDirectoryFile")) continue;
        loopdir(dynamic_cast<TDirectoryFile*>(key->ReadObj()), indent + key->GetName() + "/");
    }
}

int main(int argc, char* argv[]) {
    if (argc < 2) {
        cout << "Need to specify the filename" << endl;
        return 1;
    }

    TFile* f = new TFile(argv[1]);

    if (argc < 3) {
        cout << "Need to speficy the histogram path. The files are:" << endl;
        f->ls();
        loopdir(f);
        return 1;
    }

    TTree* tr = (TTree*)f->Get(argv[2]);
    tr->Print("all");

    return 0; 
}