Alexey Bokov’s weblog

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)


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


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 ).

• Ubuntu doesn’t asking for login after boot up ( may happen after unexpected shutdown ) :
  press Ctrl-Alt-F1 to login in terminal mode and use fsck to fix it
• Add user short memo :
[root@my-box ~]# useradd -g users -u 560 tuser
[root@my-box ~]# passwd tuser

  ps. sudo will be required in not-root case
• Proper access rights for .ssh files :
chmod 700 ~/.ssh
chmod 600 ~/.ssh/id_rsa
chmod 644 ~/.ssh/id_rsa.pub
chmod 644 ~/.ssh/authorized_keys
chmod 644 ~/.ssh/known_hosts

• List all files in folder sorted by size :
find . -type f -exec du -k "{}" \; | sort -n


Update in Amazon Web Services:

• Recursively add files and foldes into CVS

find . -type d -print | grep -v CVS | xargs -n1 cvs add

• Delete “.svn” files from current folder

find . -type f  -exec echo \"{}\" \;  | grep ".svn" | xargs rm

Some Sony Vaio owners ( my own is VGN-FZ31ER ) may have MAC is in deep sleep! problems – WiFI doesn’t work under Ubuntu because WLAN driver goes into forever sleep ( some bug in power safe logic I suppose ). This bug can be fixed by adding “noacpi” parametrs to Ubuntu boot command line.

Microsoft is offering about 20,000 lines of its own device drivers to the Linux kernel that will enable Linux to run as a guest on its Hyper-V virtualization technology. Specifically, the contributed loadable kernel modules enable Linux to run in ‘enlightened mode’, giving it efficiencies equivalent to a Windows virtual machine running on Hyper-V. Also see Redmond Releases Code to Linux Kernel Community at pcworld.com