thank you very much, it did help

python ./panda-test.py --noheaders
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

import argparse

import backtrader as bt
import backtrader.feeds as btfeeds

import pandas


def runstrat():
    args = parse_args()

    # Create a cerebro entity
    cerebro = bt.Cerebro(stdstats=False)

    # Add a strategy
    cerebro.addstrategy(bt.Strategy)

    # Get a pandas dataframe
    datapath = ('../../datas/2006-day-001.txt')
# Simulate the header row isn't there if noheaders requested
    skiprows = 1 if args.noheaders else 0
    header = None if args.noheaders else 0

    dataframe = pandas.read_csv(datapath,
                                skiprows=skiprows,
                                header=header,
                                parse_dates=True,
                                index_col=0)

    if not args.noprint:
        print('--------------------------------------------------')
        print(dataframe)
        print('--------------------------------------------------')

    # Pass it to the backtrader datafeed and add it to the cerebro
                                                      
   data = bt.feeds.PandasData(dataname=dataframe)

    cerebro.adddata(data)

    # Run over everything
    cerebro.run()

    # Plot the result
    cerebro.plot(style='bar')


def parse_args():
    parser = argparse.ArgumentParser(
        description='Pandas test script')

    parser.add_argument('--noheaders', action='store_true', default=False,
                        required=False,
                        help='Do not use header rows')

    parser.add_argument('--noprint', action='store_true', default=False,
                        help='Print the dataframe')

    return parser.parse_args()


if __name__ == '__main__':
    runstrat()

python ./panda-test.py --noheaders
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

import argparse

import backtrader as bt
import backtrader.feeds as btfeeds

import pandas


def runstrat():
    args = parse_args()

    # Create a cerebro entity
    cerebro = bt.Cerebro(stdstats=False)

    # Add a strategy
    cerebro.addstrategy(bt.Strategy)

    # Get a pandas dataframe
    datapath = ('../../datas/2006-day-001.txt')
# Simulate the header row isn't there if noheaders requested
    skiprows = 1 if args.noheaders else 0
    header = None if args.noheaders else 0

    dataframe = pandas.read_csv(datapath,
                                skiprows=skiprows,
                                header=header,
                                parse_dates=True,
                                index_col=0)

    if not args.noprint:
        print('--------------------------------------------------')
        print(dataframe)
        print('--------------------------------------------------')

    # Pass it to the backtrader datafeed and add it to the cerebro
                                                      
   data = bt.feeds.PandasData(dataname=dataframe)

    cerebro.adddata(data)

    # Run over everything
    cerebro.run()

    # Plot the result
    cerebro.plot(style='bar')


def parse_args():
    parser = argparse.ArgumentParser(
        description='Pandas test script')

    parser.add_argument('--noheaders', action='store_true', default=False,
                        required=False,
                        help='Do not use header rows')

    parser.add_argument('--noprint', action='store_true', default=False,
                        help='Print the dataframe')

    return parser.parse_args()


if __name__ == '__main__':
    runstrat()

the example ./panda-test.py --noheaders in Data-Feed panda section of the documentatioin gives an error:

feeds/pandafeed.py", line 212, in <listcomp>
    colnames = [x.lower() for x in self.p.dataname.columns.values]
AttributeError: 'numpy.int64' object has no attribute 'lower'

without --noheaders works just fine.
What is a problem with --noheaders

thank you very much, it did help

the very first BUY/SELL example in https://www.backtrader.com/docu/quickstart/quickstart/ (Do not only buy … but SELL) has problem that the execution price
of a market order is NOT the opening price of the next bar
Datafile at datapath = os.path.join(modpath, '../../datas/orcl-1995-2014.txt')
has the following content:
Date,Open,High,Low,Close,Adj Close,Volume
....
2000-01-05,25.406250,26.593750,24.000000,25.500000,22.681999,166054000
2000-01-06,25.039049,26.250000,23.671875,24.000000,21.347761,109880000

the output from the example says this:
2000-01-05, Close, 22.68
2000-01-05, BUY CREATE, 22.68
2000-01-06, BUY EXECUTED, 22.27
2000-01-06, Close, 21.35

so the opening price at 2000-01-06 is 26.593750
but the execution price is 22.27
how comes: it is not even in the trade range for this day.

second problem: the data in the webpage example does not match the data in
the file orcl-1995-2014.txt
the data in the webpage gives:
2000-01-05T00:00:00, Close, 24.05
2000-01-05T00:00:00, BUY CREATE, 24.05
2000-01-06T00:00:00, BUY EXECUTED, 23.61
2000-01-06T00:00:00, Close, 22.63

third:
how and where is the execution price set and how to find it out
some sort of trace functions calls?

please help