GNU Hacker's Meeting 2020

In 2020 the (european) GHM is going to Germany ! This time, we will be gathering in the nice city of Hamburg for hacking, learning and meeting each other.

The CCC Hamburg (Chaos Computer Club) gently offers us their Hacker Space for the GHM 2020 meeting. It's enough room for 30 people and it also has a beamer and screen that we are allowed to use.


The event will take place from Wednesday 19 August to Friday 21 August.


 [CCC Hamburg]
CCC Hansestadt Hamburg e.V.
Zeiseweg 9
22765 Hamburg
GPS coordinates:
OSM map:
GHM at CCC Hamburg
How to arrive:
If you arrive by airplane, take the metro line S1 directly at the airport to to the central station (Hauptbahnhof). Either on the same track or the neighbour track the S21/S31 will take you to Holstenstraße (3 stations into the direction "Elbgaustraße").
From there it's an estimated 5 minutes walk.
A one day ticket for public transport is 6,50€ and valid from 9:00 (until open end).
Metro plan (best stick with U and S)
The venue is quickly reachable via public transport + 5min walk. So you can take any hotel and possibly AirBnB not too far away.
But for the early birds: Dock Europe e.V. offers budget rooms with 2-4 beds in the same building.
See GuestFloor for details

They also offer breakfast (6€/per night), towels and bedding (6€/per night).

There is a promising cantina (also vegetarian) in the same building, but of course we are free to go wherever we want.
Restaurants with good vegan / vegetarian food can be found around.

CCC Hamburg offers a small kitchen and water/drink for 1,50 € per bottle.
You are free to bring your own food and drink as you like.
Getting Help:
If you need help, contact us at <>.
E.g. understanding/translating the CCC or Dock Europe pages (they are mostly in German, partly French), regarding public transport in Hamburg, etc.


To register for GHM 2020, please send us the information requested below.
First name, last name and contact email are mandatory.
All others are optional.

The number of participants is limited to 30 persons. We will update this page as soon as this number is reached.
Registering is necessary to attend the GHM. Just write us an email to the contact address below, stating your intention to come, along with the following information:

Note that attendance will be free of charge.
But of course sleeping accomodation, food, drink, etc. is your own business.

Call For Talks

We will be hosting a single track of talks during all three days. The venue provides a nice room with beamer, internet connection, power plugs, etc.

If you fancy to give a talk, presentation, a show-and-tell, whatever, please let us know in the contact address below, along with the following information, for each talk:


All the talks and activities below will take place at Docker Europe e.V.

Wednesday 19 August

Thursday 20 August

Friday 21 August


GNU poke, an extensible editor for structured binary

Author: Jose E. Marchesi

GNU poke is a new interactive editor for binary data. Not limited to editing basic entities such as bits and bytes, it provides a full-fledged procedural, interactive programming language designed to describe data structures and to operate on them. Once a user has defined a structure for binary data (usually matching some file format) she can search, inspect, create, shuffle and modify abstract entities such as ELF relocations, MP3 tags, DWARF expressions, partition table entries, and so on, with primitives resembling simple editing of bits and bytes. The program comes with a library of already written descriptions (or "pickles" in poke parlance) for many binary formats.

GNU poke is useful in many domains. It is very well suited to aid in the development of programs that operate on binary files, such as assemblers and linkers. This was in fact the primary inspiration that brought me to write it: easily injecting flaws into ELF files in order to reproduce toolchain bugs. Also, due to its flexibility, poke is also very useful for reverse engineering, where the real structure of the data being edited is discovered by experiment, interactively. It is also good for the fast development of prototypes for programs like linkers, compressors or filters, and it provides a convenient foundation to write other utilities such as diff and patch tools for binary files.

This talk (unlike Gaul) is divided into four parts. First I will introduce the program and show what it does: from simple bits/bytes editing to user-defined structures. Then I will show some of the internals, and how poke is implemented. The third block will cover the way of using Poke to describe user data, which is to say the art of writing "pickles". The presentation ends with a status of the project, a call for hackers, and a hint at future works.


For subscriptions, talk proposals, or any other inquiry, suggestion, etc., please contact <>.

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