compress PDF on console via ghostscript

You can compress PDFs pretty easily on comandline with ghostscript:
gs -sDEVICE=pdfwrite -dNOPAUSE -dBATCH -sOutputFile=output_file.pdf input_file.pdf

Fun with TCC and C-scripting

Fabrice Bellards superfast tiny C Compiler TCC can be invoked from scripts, just as shell scripts. This makes C possible to use as kind of a scripting language.

[read more]

Installing openvpn and connect via ssh to a remote machine

OpenVPN is an open source software application that implements virtual private network (VPN) techniques for creating secure point-to-point or site-to-site connections in routed or bridged configurations and remote access facilities.

[read more]


Simple command line tool to convert a HTML document to a PDF document using the Webkit Rendering Engine and QT.

[read more]

OWASP Top 10 2013-Risk

The Open Web Application Security Project (OWASP) is an open community dedicated to enabling organizations to develop, purchase, and maintain applications that can be trusted.

[read more]

Trick for blocking email spam

Fake MX records can work like greylisting and often much faster. It doesn’t require the installation of new software. What you do is add a fake highest and lowest MX record. Normal email will probably retry but spammers often don’t. This is especially true of virus infected windows zombie spam. Here’s an example MX configuration.

[read more]


“Während sich Wirtschaft und Politik fieberhaft und nahezu täglich neue Anwendungsmöglichkeiten für die kleinen RFID-Schnüffelchips ausdenken, behalten wir, der FoeBuD e.V. in Bielefeld, die Folgen dieser neuen Technik für unsere Menschen- und Bürgerrechte im Blick. Mit Erfolg.”

[read more]

Character Analyzer

Little webtool to analyze the characters of a string. Works well for all charsets except the really exotic ones (e.g. the samaritan charset).

That a character is displayed properly on your machine depends on the browser that you are using and the fonts installed on your computer (and properly set browseroptions that determine the fonts used to display particular character sets, encodings or languages of course).

Character Analyzer

visit the Character Analyzer now!

Some Links:

The Unicode Consortium

Repeat after me: Unicode is not UTF Joel on Software

von-Neumann-Probe Simulator

A von-Neumann-probe is a self-replicating probe, designed to discover and analyze a remote system. By collecting certain materials such as minerals or fossiles, the probe will be able to clone itself based on a given construction plan or genetic blueprint. The concept behind this idea is named after Hungarian American mathematician and physicist John von Neumann. von-neumann-simulator visit Simulation

Breaking Captchas with humans

“We’re all familiar with CAPTCHA right? That impenetrable fortress of crazy squiggly characters that only a real human can decipher. Whilst they tend to drive us a bit nuts, they do actually provide a valuable function in that they prevent the automation of requests against online services.”
Troy Hunt

[read more]

a little Brainfuck

++++++++++ [ > ++++++++++ > ++++++ <<- ] > +++++.+++++.--------.+++++++++. > ++++. <<++ [ > ++ <- ] > .---.-------.----.+++++++.++++.++.---------.+++++. <+++ [ > ++++ <- ] > . <++++ [ > ---- <- ] > -.+++++++. <++++++ [ >> --- <<- ] >> . <-------------.++++++++++++.--.
JavaScript interpreter
About Brainfuck

My Zen of Python

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Special cases aren't special enough to break the rules.
Practicality beats purity.
Errors should never pass silently, unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one obvious way to do it.

Linux snippets

Just a small, unsorted collection of Linux commandline snippets. Just for myself mostly.

[read more]

Some notes on HTTP headers

HTTP-Headers: Extra-Informations, which are added to HTTP-request and response messages in a client-server-communication.

[read more]

Some notes on cURL

Little powerful command-line tool by Daniel Stenberg for transferring data between computers in networks using various protocols such as http, https or ftp.

[read more]

Some notes on Telnet

Remember this funky little network protocol TELNET, which has been invented in the early 70ies? Telnet provides access to a command line interface CLI on a remote host over TCP/IP.

[read more]