Alexey Bokov's weblog

Where’s Sun JDK on Ubuntu 10.04 ?

Alexey Bokov — Thu, 19 Aug 2010 13:46:08 +0000

By unknown reasons Sun JDK was moved to partner repository, so to use sun jdk you need to do this steps
sudo add-apt-repository "deb http://archive.canonical.com/ lucid partner" sudo apt-get update sudo apt-get upgrade
and then enjoy :
sudo apt-cache search jdk | grep sun sun-java6-source - Sun Java(TM) Development Kit (JDK) 6 source files sun-java6-jre - Sun Java(TM) Runtime Environment (JRE) 6 (architecture independent files) sun-java6-jdk - Sun Java(TM) Development Kit (JDK) 6 sun-java6-javadb - Java(TM) DB, Sun Microsystems' distribution of Apache Derby sun-java6-demo - Sun Java(TM) Development Kit (JDK) 6 demos and examples sun-java6-bin - Sun Java(TM) Runtime Environment (JRE) 6 (architecture dependent files)

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Cloud computing links – August 2010

Alexey Bokov — Wed, 18 Aug 2010 10:59:21 +0000

Shanghai releases 3-year cloud computing plan – Shanghai plans to use cloud computing technologies in urban management, industry development, e-government and small and medium-sized enterprise services

AWS related links :

State of the cloud – 2010 August
Amazon’s EC2 Generating 220M+ Annually – really interesting post – “at 40,000 servers evenly distributed across 6 availability zones we know, ___ 6,700 servers per zone..Most of the servers are likely in the US availability zones vs. the EU zones, maybe 75-80% of total capacity”. Also take a look on amazon ec2 instances usage rates
Anatomy of an Amazon EC2 Resource ID and based on this anatomy EC2 usage estimates
Rumor Mill: Google EC2 Competitor Coming in 2010?

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bash tips – convert to lowercase

Alexey Bokov — Wed, 11 Aug 2010 13:27:18 +0000

You can use sed :
sed -e 's/$[^\d]*$/\L\1/' in.txt > out.txt
or perl inliner :
perl -ne 'utf8::decode $_; $_ = lc $_; utf8::encode $_; print' in.txt > out.txt.
Both guys works fine for unicode file too.

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telnet in bash scripts

Alexey Bokov — Thu, 29 Jul 2010 13:34:01 +0000

Using telnet in bash scripts to automate some stuff ? It’s really easy, here’s an example to tell “hello world” on telnet server :

req="hello world" server="my_server 1234" val=`( echo open ${server} sleep 3 echo "${req}" sleep 1 ) | telnet` echo $val

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How to create list of screenshots for list of urls ?

Alexey Bokov — Tue, 20 Jul 2010 13:34:24 +0000

Okay, we have text file with list of urls and want to have firefox’s screenshots from this pages and also we need to have this screenshots in some normalized resolution ( like all images should be in 300×400 – thumbnails ). First of all you need to install Command line print Firefox add-on. Then create some simple script which will run firefox with needed url, print screenshot and close ( in my case via kill – may be it’s too brutal ) firefox in cycle. It may look like this ( url_list.txt – file with urls – each url on its own line ), after running this script you will have many *.png files which is screenshots for ulrs – 0.png – for first url in urls_list.txt, 1.png for second and so on.
#!/bin/bash id=0 while read line do firefox -print $line -printmode png -printdelay 10 -printfile ${id}.png ps ax | grep firefox | awk '{ print $1 }' | xargs kill -9 ; id=$[$id+1] done < urls_list.txt

And now then we have screenshots ( all this guys are in different resolution in common ) then we need to normalize them – to create thumbnails for all images in 300×400 resolution – convert helps!
for f in *.png; do convert -thumbnail 300x400! ${f} thumb_${f} done
And we have many thumb_*.pn with 300×400 resolution all. A little note – using resolution without ! sign will work in another way – resize will be processed proportionally with using resize only for one dimension ( bigger one ).

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Interesting links ( June/July 2010 )

Alexey Bokov — Fri, 11 Jun 2010 09:09:27 +0000

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Version control systems ( git, svn, cvs, mercury ) links

Alexey Bokov — Tue, 08 Jun 2010 15:34:23 +0000

GIT

git for big files : git-bigfiles
omit large files commiting into git repo : Rejecting large files in git
git as backup system : A better backup system based on Git and Journey to a backup solution: Git
Hosting Git repositories, The Easy (and Secure) Way

Subversion ( svn )

How to store-all-stuff-in-svn : Subverting your homedir, or keeping your life in svn
SVN-Hooks : Avoid empty comment in SVN commits
Using SVN-Hooks to commit notifications on email : Setting up a post-commit mail notification for a Subversion repository
SVN Notify documentation

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C++ links

Alexey Bokov — Mon, 07 Jun 2010 16:26:45 +0000

Hash tables :

Network Applications of Bloom Filters: A Survey – by Andrei Brodery and Michael Mitzenmacherz

Coding bloom filters

General Purpose Hash Function Algorithms

IP-Lookup with a Blooming Tree Array: A New Lookup

Algorithm for High Performance Routers

C++ Q/A :

Bjarne Stroustrup’s C++ Style and Technique FAQ

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A little bit of cloud computing humor

Alexey Bokov — Mon, 07 Jun 2010 16:03:00 +0000

Cloud computing is a term that originally meant elastic on demand computing but is now a term applied elastically by marketdroids to any form of virtualisation.
This is part of the transition from 2009′s vBullshit to BaaS, Bullshit as a Service.

via chapmancentral.demon.co.uk

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The Web as graph – fast diameter estimation, massive Peta-Scale graphs mining, hadoop and MapReduce

Alexey Bokov — Wed, 26 May 2010 14:04:54 +0000

The Web as a graph by Ravi Kumar, Prabhakar Raghavan, Sridhar Rajagopalan,Eli Upfaly, Andrew S. Tomkins
The Web as a graph: measurements, models, and methods
Web Graph and PageRank algorithm by Danil Nemirovsky
Parallel implementation of graph diameter algorithms
Diameter of the World-Wide-Web
Fast Computation of Empirically Tight Bounds for the Diameter of Massive Graphs Cl ?mence Magnien 1 , Matthieu Latapy 1 and Michel Habib
Structural Analysis of the Web
Small world phenomenon
Fast Radius Plot and Diameter Computation for Terabyte Graphs (SDM 2010)
Probabiblistic Counting algorithms for Database applications by Philippe Flajolet
Philippe Flajolet home page
HADI: Fast Diameter Estimation and Mining in Massive Graphs with Hadoop
U Kang personal home page – one of HADI authors
Data Mining with M AP R EDUCE: Graph and Tensor Algorithms with Applications
PEGASUS: Mining Peta-Scale Graphs

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