Running ipython notebook on a remote (outdated) ubuntu system

Posted on 2014-02-08 by tik0

Note: Jump to the end of this post to install a basic ipython-notebook environment.

ipython notebook is one of the most impressive things I’ve seen the last few years. You can reache outstanding results wich are documented and calculated on the same page. So no more paper war and mixed solutions for my problems anymore ;).

But while I get more and more different systems/computers and laptops, it’s hard to keep track of a consistent notebook. One could say: Use git or subversion. But then it comes to the point where you want to show some other guys your results in the bus and you want to change some variables, or add some new ideas (Assuming that you have internet everywhere nowadays). At that point even the notebook-viewer in combination with git becomes (more or less) futile.

So what do we want:

An remote ipython notebook with up-to-date packages
Secured from the rest of the world
A secured write/execute-mode
A read-only mode (so that we can distribute our achivements to privileged poeple)
git (optionaly and not discussed here)

What do we have: A remote server running Debian, with a non up-to-date repository.

While the points 2.-4. can be solved using this solution, the remote server becomes a problem, due to the fact that it has mostly a very stable but very outdated package repository. This leads to ugly outdated or non existing packages. In my case even the standard install routine from the ipython webpage did not work:

sudo apt-get install ipython-notebook python-matplotlib \
                     python-scipy python-pandas python-sympy python-nose

1 2	sudo apt-get install ipython-notebook python-matplotlib \ python-scipy python-pandas python-sympy python-nose

In this case, you have to use pip, which downloads the current packages from PyPI and compiles them for your system. As you can imagine, you need a bunch of dev packages. So here comes the solution at a glance:

# First we need some python and pip
apt-get install python python-pip 
# Now lets install some necessary dependencies for installing with pip
apt-get install python-dev.all libfreetype6 libfreetype6-dev \
                libpng12-dev gfortran libblas-dev liblapack-dev \
                pandoc
# Finaly, lets get the newest packages
pip install ipython
pip install matplotlib
pip install pyzmq
pip install jinja2
pip install scipy
pip install pandas
pip install sympy
pip install nose
pip install pygments  # For html conversion
pip install sphinx    # For latex conversion
<span style="font-family: 'Courier 10 Pitch', Courier, monospace; font-size: 12px; font-style: normal; line-height: 1.5;"># Running the notebook
ipython notebook</span>

# First we need some python and pip

apt-get install python python-pip

# Now lets install some necessary dependencies for installing with pip

apt-get install python-dev.all libfreetype6 libfreetype6-dev \

libpng12-dev gfortran libblas-dev liblapack-dev \

pandoc

# Finaly, lets get the newest packages

pip install ipython

pip install matplotlib

pip install pyzmq

pip install jinja2

pip install scipy

pip install pandas

pip install sympy

pip install nose

pip install pygments # For html conversion

pip install sphinx # For latex conversion

<span style="font-family: 'Courier 10 Pitch', Courier, monospace; font-size: 12px; font-style: normal; line-height: 1.5;"># Running the notebook

ipython notebook</span>

A nice conversion from notebook to a PDF document:

ipython nbconvert MyNotebook.ipynb --SphinxTransformer.author="The Author" --to latex --post PDF

1	ipython nbconvert MyNotebook.ipynb --SphinxTransformer.author="The Author" --to latex --post PDF

Blocking bad IPs using badips.com API

Posted on 2014-01-08 by tik0

Regarding this post http://www.badips.com/blog/scores-are-here now the API for scores work. Now it is possible to use it for e.g. enhance your iptables to block all the bad IPs which have been reported to http://www.badips.com/.
Afterwards you’ll find two scripts which are able to use the API and block the reported IPs. The first one is able to use the hosts.deny file. The second one defines rules in iptables. Another way could be the use of ipset, but for now you can choose between these two ways.

Script for hosts.deny:

#!/bin/bash
# Script for blocking IPs which have been reported to www.badips.com
# Usage: Just execute with root privileges
# ---------------------------

_file=/etc/hosts.deny  # Location of the hosts.deny files (might be correct)
_input=badips.db       # Name of database (will be downloaded with this name)
_level=5               # Blog level: not so bad/false report (0) over confirmed bad (3) to qui$
_service=ssh           # Logged service (see www.badips.com for that)
_tmp=tmp               # Name of temporary file

# Get the bad IPs
wget -qO- http://www.badips.com/get/list/${_service}/$_level > $_input || { echo "$0: Unable to download ip list."; exit 1; }

# Define some start and end quotes for detecting the IPs defined by this script
_start="# ##### start block list -- DO NOT EDIT #####"
_end="# ##### end block list #####"

# Delete the old entries
_line_start=`grep -x -n "$_start" $_file | cut -f1 -d:`
_line_end=`grep -x -n "$_end" $_file | cut -f1 -d:`
_lines=`wc -l < $_file`

# Chop the old block if it exists
if [[ "$_line_start" != " " ]]
then
    head -n`expr $_line_start - 1` $_file > $_tmp
    tail -n`expr $_lines - $_line_end` $_file >> $_tmp
else
    cp $_file $_tmp
fi

# Add the new entries
echo $_start >> $_tmp
cat $_input | sed "s/^/ALL\:\ /g" >> $_tmp
echo $_end >> $_tmp

# Replace and cleanup the old file
mv $_tmp $_file
rm $_input

exit 0

#!/bin/bash

# Script for blocking IPs which have been reported to www.badips.com

# Usage: Just execute with root privileges

# ---------------------------

_file=/etc/hosts.deny # Location of the hosts.deny files (might be correct)

_input=badips.db # Name of database (will be downloaded with this name)

_level=5 # Blog level: not so bad/false report (0) over confirmed bad (3) to qui$

_service=ssh # Logged service (see www.badips.com for that)

_tmp=tmp # Name of temporary file

# Get the bad IPs

wget -qO- http://www.badips.com/get/list/${_service}/$_level > $_input || { echo "$0: Unable to download ip list."; exit 1; }

# Define some start and end quotes for detecting the IPs defined by this script

_start="# ##### start block list -- DO NOT EDIT #####"

_end="# ##### end block list #####"

# Delete the old entries

_line_start=`grep -x -n "$_start" $_file | cut -f1 -d:`

_line_end=`grep -x -n "$_end" $_file | cut -f1 -d:`

_lines=`wc -l < $_file`

# Chop the old block if it exists

if [[ "$_line_start" != " " ]]

then

head -n`expr $_line_start - 1` $_file > $_tmp

tail -n`expr $_lines - $_line_end` $_file >> $_tmp

else

cp $_file $_tmp

# Add the new entries

echo $_start >> $_tmp

cat $_input | sed "s/^/ALL\:\ /g" >> $_tmp

echo $_end >> $_tmp

# Replace and cleanup the old file

mv $_tmp $_file

rm $_input

exit 0

Script for iptables:

#!/bin/bash
# Script for blocking IPs which have been reported to www.badips.com
# Usage: Just execute by e.g. cron every day
# ---------------------------

_ipt=/sbin/iptables    # Location of iptables (might be correct)
_input=badips.db       # Name of database (will be downloaded with this name)
_pub_if=eth0           # Device which is connected to the internet (ex. $ifconfig for that)
_droplist=droplist     # Name of chain in iptables (Only change this if you have already a chain with this name)
_level=5               # Blog level: not so bad/false report (0) over confirmed bad (3) to quite aggressive (5) (see www.badips.com for that)
_service=ssh           # Logged service (see www.badips.com for that)

# Get the bad IPs
wget -qO- http://www.badips.com/get/list/${_service}/$_level > $_input || { echo "$0: Unable to download ip list."; exit 1; }

### Setup our black list ###
# First flush it
$_ipt --flush $_droplist
# Create a new chain
$_ipt -N $_droplist

# Filter out comments and blank lines
# store each ip in $ip
for ip in `cat $_input`
do
    # Append everything to $_droplist
    $_ipt -A $_droplist -i ${_pub_if} -s $ip -j LOG --log-prefix "Drop Bad IP List"
    $_ipt -A $_droplist -i ${_pub_if} -s $ip -j DROP
done

# Finally, insert or append our black list
$_ipt -I INPUT -j $_droplist
$_ipt -I OUTPUT -j $_droplist
$_ipt -I FORWARD -j $_droplist

exit 0

#!/bin/bash

# Script for blocking IPs which have been reported to www.badips.com

# Usage: Just execute by e.g. cron every day

# ---------------------------

_ipt=/sbin/iptables # Location of iptables (might be correct)

_input=badips.db # Name of database (will be downloaded with this name)

_pub_if=eth0 # Device which is connected to the internet (ex. $ifconfig for that)

_droplist=droplist # Name of chain in iptables (Only change this if you have already a chain with this name)

_level=5 # Blog level: not so bad/false report (0) over confirmed bad (3) to quite aggressive (5) (see www.badips.com for that)

_service=ssh # Logged service (see www.badips.com for that)

# Get the bad IPs

wget -qO- http://www.badips.com/get/list/${_service}/$_level > $_input || { echo "$0: Unable to download ip list."; exit 1; }

### Setup our black list ###

# First flush it

$_ipt --flush $_droplist

# Create a new chain

$_ipt -N $_droplist

# Filter out comments and blank lines

# store each ip in $ip

for ip in `cat $_input`

# Append everything to $_droplist

$_ipt -A $_droplist -i ${_pub_if} -s $ip -j LOG --log-prefix "Drop Bad IP List"

$_ipt -A $_droplist -i ${_pub_if} -s $ip -j DROP

done

# Finally, insert or append our black list

$_ipt -I INPUT -j $_droplist

$_ipt -I OUTPUT -j $_droplist

$_ipt -I FORWARD -j $_droplist

exit 0

bad IPs

Posted on 2013-11-11 by tik0

After nmap-ing my on of my servers, I found some ugly IPs trying to bruteforce my SSH accounts.
After writing a script for my SSH deamon which logs bad IPs and add them to hosts.deny, I thought about all the other deamons on my server.

Not willing to write fancy scripts for all the others, I installed the nice tool fail2ban which add bad IPs to a local banlist.
It works like a charm and the best of all: There is a nice frontend call bad IPs.
A nice visualization for every server owner

Erlösung des UnityMedia Technicolor tc7200

Posted on 2013-10-18 by tik0

Einer meiner größten Fehler den ich je begangen habe, war zu UnityMedia (UM) zu wechseln. Geblendet von den tollen Angeboten konnte ich mir vor ca. einem Monat noch nicht ausmalen, welche Probleme da auf mich zukommen. Neben dem DS-Lite, was ja noch so gerade zu verkraften ist, wird von UM ein absolut fehlerhaftes, nicht funktionsfähiges und sicherheitstechnisch bedenklicher Modem/Router ausgeliefert:
Das Technicolor tc7200
Hier ist ein schöner Blog der den ganzen Frust konzentriert und auf dem ich in den Kommentaren selbst partizipiert habe:
kabelbw-technicolor-freies-internet-ist-uns-egal
Nach sehr viel Hin und Her habe ich beim technischen Service eine Person am Hörer gehabt, welche mir erklärte, wie man es denn am wahrscheinlichsten schafft ein Cisco Modem zu erhalten. Zunächst ist es erst einmal unmöglich dies am Telefon zu schaffen, da die Leute nicht die Berechtigungen haben Gerät A gegen B zu tauschen (nur A gegen A). Somit bleibt nur die Mail an den Kundenservice (die dürfen A gegen B tauschen) von UM mit dem Betreff “Beschwerde”.

Nachfolgend die Mail, woraufhin mir ein “Cisco EPC3208G EuroDocsis 3.0 2-PORT” und ein “DLink DIR-600” geschickt wurde:

Date: Wed, 09 Oct 2013 09:31:48 +0200 From: Timo ??? To: kundenservice@unitymedia.de Subject: Beschwerde - Kundenummer ???????? - tc7200 Problem

Sehr geehrte Damen und Herren von UnityMedia,

nach Rücksprache mit ihrem telefonischen Kundendienst wende ich mich,
unter deren Anweisungen, nun an Sie.

Wie Sie wahrscheinlich aus dem Verlauf, den Sie in Ihrer Datenbank unter
meiner Kundennummer, herauslesen, besteht seit Inbetriebnahme der
Internetverbindung ein kontinuierlich Problem mit der Internetverbindung.
Sie ist entweder gar nicht, oder nur sporadisch vorhanden.
Ihre Techniker, die sowohl die Leitung bis zu meinem Hausanschluss, als
auch den Anschluss innerhalb der Wohnung geprüft haben, konnten Seitens
der Verkabelung keinen Fehler feststellen.
Sowohl die Techniker, als auch verschiedene Kontaktpersonen Ihres
telefonischen Kundenservices haben mir bestätigt, dass der Fehler
eindeutig durch das Gerät tc7200 verursacht wird.

Unter der Anweisung Ihres Kundendienstes wende ich mich nun mit der
folgenden Bitte an Sie:
Tauschen Sie das Gerät gegen ein Funktionierendes, nicht tc7200, aus.

Einer meiner Arbeitskollege hat sich mit der gleichen Problematik an Sie
gewandt, und das folgende Produkt im Austausch von Ihnen erhalten:
Cisco EPC3208 EuroDocsis 3.0 2-PORT EMTA
Seitdem erfreut er sich einer funktionierenden und unterbrechungsfreien
Internetverbindung.

Ich bitte Sie den Fehler schnellst möglich zu beheben, ohne mich auf ein
bald kommendes Firmwareupdate des tc7200 zu verweisen.
Andernfalls nehme ich mein Sonderkündigungsrecht in Anspruch, welches
bei einer unzureichenden Bereitstellung des Internets und
Nichtbeseitigung des Fehlers innerhalb von 4 Wochen, greift.

Mit freundlichen Grüßen,
Timo ???

it’s OWL – Summerschool

Posted on 2013-10-04 by tik0

Eine wunderschöne und sehr fordernde Woche durfte ich letztens bei der Teilnahme der “it’s OWL Summerschool” erfahren. Das Leitthema war “Industrie 4.0″, “Cyberphysical Systems” und “Self-X”. Auch wenn diese Themen noch weit in der Zukunft (> 2020) liegen, so ist die Region OWL ein wichtiger Trendsetter und Impulsgeber für diese neuen Technologien.
Pressemitteilung

Using vncviewer without typing in the password

Posted on 2013-05-21 by tik0

Hi,

it is more convenient to use vncviewer without typing in the password all the time.
To do so, just create an own password-file in the following way:

$ # Create the passwd file in the home-directory for the e.g. movie server
$ vncpasswd -f > ~/movieSVR.passwd

1 2	$ # Create the passwd file in the home-directory for the e.g. movie server $ vncpasswd -f > ~/movieSVR.passwd

After you typed in the password twice in plain text, just use the created file to connect to the server:

$ # Connect to the server "movieSVR.com" with the password file
$ vncviewer movieSVR.com -p ~/movieSVR.passwd

1 2	$ # Connect to the server "movieSVR.com" with the password file $ vncviewer movieSVR.com -p ~/movieSVR.passwd

Greetz!

Remapping Caps-Lock under XServer to call e.g. konsole

Posted on 2013-04-25 by tik0

Hi there,

isn’t it horrible if you write a text and suddenly THIS HAPPens.
So while Caps-Lock is the most useless key, one could ask for a remapping to a more usefull key or action (call the console).

So let’s check out how to remap the Caps-Lock key using xmodmap:
First we need to unmap the Caps-Lock from the special mappings:

$ xmodmap -e "remove lock = Caps_Lock"

1	$ xmodmap -e "remove lock = Caps_Lock"

Now we need to figure it out, which keycode belongs to the Caps-Lock key. While using th tool xev and pressing Caps-Lock, we can see that keycode 66 belongs to the key Caps-Lock and that it is mapped to Caps_Lock. (The number of the keycode is the unique identyfier regarding a key and the keysymname like Caps_Lock is the reinterpretation of the XServer).

Whit the keycode we can now do a remap to any other key like … let us use an unused one like F13:

$ xmodpap -e "keycode 66 = F13"

1	$ xmodpap -e "keycode 66 = F13"

Now what can we do with F13? Using KDE and global shortcuts (SystemSettings -> Shortcuts and Gestures -> Edit -> New -> Global Shortcut -> Command/URL), we can bind any action to F13. I use it for calling “konsole” which saves a lot of time while working.

The keymapping will be lost after the next login, so we need to make the remapping permanent. Create a new file in your homefolder which will be executed by xmodmap after every login:

$ kate ~/.Xmodmap

1	$ kate ~/.Xmodmap

Now add the following lines:

! Comment: Remove Caps_Lock from special mapping
remove lock = Caps_Lock
! Comment: Tell xmodmap that key 66 (former Caps_Lock) is now F13
keycode 66 = F13

! Comment: Remove Caps_Lock from special mapping

remove lock = Caps_Lock

! Comment: Tell xmodmap that key 66 (former Caps_Lock) is now F13

keycode 66 = F13

Well done!

Matlab: Build-In vs. MEX vs. “naiv” loops

Posted on 2013-04-12 by tik0

Hi,

ich wurde vor kurzem nach einem Minimalbeispiel für eine MEX-Funktion in MATLAB gefragt, da ich so davon geprahlt habe. Wer MEX nicht kennt, dass sind “MATLAB EXecutables”, welche in C/C++ oder Fortran geschrieben werden können. Sofern man diese dann mit dem MEX-Compiler übersetzen kann, ruft man sie straight-forward aus einem Matlab-Skript auf. Dies führt unter Umständen zu einem gewaltigen Geschwindigkeitsschub, in Bezug auf eine gleiche Implementierung in MATLAB.

Als Minimalbeispiel habe ich mir die Spaltensummenfunktion überlegt, welche alle Zeileneinträge einer Spalte subsummiert. In Matlab ist diese bereits implementiert und kann wie folgt genutzt werden:

>> sum([ 1 2 3; 1 2 3])
ans =
     2   4   6

>> sum([ 1 2 3; 1 2 3])

ans =

2 4 6

Eine äquivalente MEX-Funktion sieht wie folgt aus:

#include "mex.h"

// By Timo Korthals
// Add, for the cols of a matrix:    [ 2 4 6 ] = sumcol([1 2 3;1 2 3])

double ColSum(double* matrix, double* colSumMatrix, unsigned int NumRows, unsigned int NumCols) {
    // Iterate through every col
    for(unsigned int IdxCol = 0; IdxCol < NumCols; IdxCol++) {
        // Iterate through every row
        colSumMatrix[IdxCol] = matrix[IdxCol*NumRows];
        for(unsigned int IdxRow = 1; IdxRow < NumRows; IdxRow++) {
            colSumMatrix[IdxCol] += matrix[IdxRow+IdxCol*(NumRows)];
        }
    }
}

void mexFunction(int nlhs,       mxArray *plhs[ ],
                 int nrhs, const mxArray *prhs[ ]) {
    // Some declarations
    double* matrix;
    double* colSumMatrix;
    unsigned int NumRows = mxGetM(prhs[0]);
    unsigned int NumCols = mxGetN(prhs[0]);

    // Alloc output
    plhs[0] = mxCreateDoubleMatrix(1, NumCols, mxREAL);

    // Assigne matrix to the input
    matrix       = mxGetPr(prhs[0]);
    // Assigne colSumMatrix to the output
    colSumMatrix = mxGetPr(plhs[0]);

    // Calculate the col.-sum
    ColSum(matrix, colSumMatrix, NumRows, NumCols);
}

#include "mex.h"

// By Timo Korthals

// Add, for the cols of a matrix: [ 2 4 6 ] = sumcol([1 2 3;1 2 3])

double ColSum(double* matrix, double* colSumMatrix, unsigned int NumRows, unsigned int NumCols) {

// Iterate through every col

for(unsigned int IdxCol = 0; IdxCol < NumCols; IdxCol++) {

// Iterate through every row

colSumMatrix[IdxCol] = matrix[IdxCol*NumRows];

for(unsigned int IdxRow = 1; IdxRow < NumRows; IdxRow++) {

colSumMatrix[IdxCol] += matrix[IdxRow+IdxCol*(NumRows)];

}

void mexFunction(int nlhs, mxArray *plhs[ ],

int nrhs, const mxArray *prhs[ ]) {

// Some declarations

double* matrix;

double* colSumMatrix;

unsigned int NumRows = mxGetM(prhs[0]);

unsigned int NumCols = mxGetN(prhs[0]);

// Alloc output

plhs[0] = mxCreateDoubleMatrix(1, NumCols, mxREAL);

// Assigne matrix to the input

matrix = mxGetPr(prhs[0]);

// Assigne colSumMatrix to the output

colSumMatrix = mxGetPr(plhs[0]);

// Calculate the col.-sum

ColSum(matrix, colSumMatrix, NumRows, NumCols);

}

Der obige code kann als colsum.cpp gespeichert werden und wie folgt kompiliert und ausgeführt werden:

>> mex sumcol.cpp; sumcol([1 2 3;1 2 3])
ans =
     2   4   6

>> mex sumcol.cpp; sumcol([1 2 3;1 2 3])

ans =

2 4 6

Evaluierung

Nun kommt der spannende Teil. Wie macht sich die MEX-Funktion im Vergleich zu einer naiven Schleifen-, semi-naiven Schleifen- und der MATLAB-Build-In-Implementierung. Hier ein kleines Evaluationsskript in MATLAB:

%% Init
NumCols = 10000;
NumRows = 10000;
A = ones(NumRows, NumCols);
ColSum = zeros(1, NumCols);

%% (1) Matlab naive implementation
ColSum = zeros(1, NumCols);
tic
for ColIdx = 1 : NumCols
    for RowIdx = 1 : NumRows
      ColSum(ColIdx) = ColSum(ColIdx) + A(RowIdx, ColIdx);
    end
end
fprintf('(1) Naive:      %f s\n',toc);

%% (2) Matlab semi-naive implemention
ColSum = zeros(1, NumCols);
tic
for ColIdx = 1 : NumCols
    ColSum(ColIdx) = sum(A(:, ColIdx));
end
fprintf('(2) Semi-naive: %f s\n',toc);

%% (3) Matlab build-in implemention
ColSum = zeros(1, NumCols);
tic
ColSum = sum(A);
fprintf('(3) Build-in:   %f s\n',toc);

%% (4) MEX implemention
ColSum = zeros(1, NumCols);
tic
ColSum = sumcol(A);
fprintf('(4) MEX:        %f s\n',toc);

%% Init

NumCols = 10000;

NumRows = 10000;

A = ones(NumRows, NumCols);

ColSum = zeros(1, NumCols);

%% (1) Matlab naive implementation

ColSum = zeros(1, NumCols);

tic

for ColIdx = 1 : NumCols

for RowIdx = 1 : NumRows

ColSum(ColIdx) = ColSum(ColIdx) + A(RowIdx, ColIdx);

end

fprintf('(1) Naive: %f s\n',toc);

%% (2) Matlab semi-naive implemention

ColSum = zeros(1, NumCols);

tic

for ColIdx = 1 : NumCols

ColSum(ColIdx) = sum(A(:, ColIdx));

end

fprintf('(2) Semi-naive: %f s\n',toc);

%% (3) Matlab build-in implemention

ColSum = zeros(1, NumCols);

tic

ColSum = sum(A);

fprintf('(3) Build-in: %f s\n',toc);

%% (4) MEX implemention

ColSum = zeros(1, NumCols);

tic

ColSum = sumcol(A);

fprintf('(4) MEX: %f s\n',toc);

Hier die Auswertung des Skriptes auf einem i7 970:

(1) ist buchstäblich die Umsetzung der Mex-Funktion in Matlab -> ca 8 s

(2) unter Teil-Ausnutzung der sum()-Funktion von Matlab -> ca 0.25 s

(3) unter Ausnutzung der sum()-Funktion von Matlab -> ca 0.07 s

(4) MEX-Funktion -> ca 0.4 s

Es gilt also bei MATLAB immer folgendes zu beachten, wenn es um Implementierungen mittels Schleifen geht:

MATLAB-BuildIn-Funktionen vor MEX-Funktionen evtl. vor Schleifen verwenden!

LaTeX symbol classifier

Posted on 2013-04-08 by tik0

I am writing my masterthesis right now and after a few non-everyday equations, I was tired of searching for the right LaTeX command in Google to generate the proper math symbol.
But then I remembered a tool called “LaTeX symbol classifier” which link I have stored deep down in my bookmarks. With this, you just need to print the symbol with your mouse, and you will be pleased will the most probable commands in LaTeX.

->LaTeX symbol classifier<-

This is a tool which shows IT at-it’s-best ;-). I’m wondering if they use HMMs for recognising like the Hanzi recognisers do.

Nice places in Beijing

Posted on 2013-01-11 by tik0

Found an old file for some nice places in near BeiHang University in Beijing. Take a look here:
->GoogleMaps<-

M	T	W	T	F	S	S
« Feb
					1	2
3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	19	20	21	22	23
24	25	26	27	28	29	30
31

Nothing more, …

… nothing less

Running ipython notebook on a remote (outdated) ubuntu system

Blocking bad IPs using badips.com API

bad IPs

Erlösung des UnityMedia Technicolor tc7200

it’s OWL – Summerschool

Using vncviewer without typing in the password

Remapping Caps-Lock under XServer to call e.g. konsole

Matlab: Build-In vs. MEX vs. “naiv” loops

Evaluierung

MATLAB-BuildIn-Funktionen vor MEX-Funktionen evtl. vor Schleifen verwenden!

LaTeX symbol classifier

Nice places in Beijing