News: Programming with google-blocky

It's fun. You can try or your children.
Blockly is a web-based, graphical programming language. Users can drag blocks together to build an application. No typing required.

You can see more on google project.

Show large image like thumbnails in firefox using greasemonkey

Today I focused on a problem you often encounter.

We have a web folder containing a series of large image files. We want to see the folder that contains but would be difficult to download all the images and then view them search to find a picture of us.

I installed Greasemonkey addon and I began to study how it works.

I don't have experience with javascript programming.

I still managed to make the script below:

// ==UserScript==
// @name        show-image
// @namespace   show-image
// @description show images from files
// @include     http://*
// @version     0.1
// ==/UserScript==
var elements = document.getElementsByTagName("a");
  for (var i=0; (anchor=elements[i]); i++) {
   src = anchor.getAttribute("href");
  if (src.indexOf('.gif') > -1 || src.indexOf('.jpg') > -1 || src.indexOf('.JPG') > -1 || src.indexOf('.jpeg') > -1)
  {
    img = document.createElement('img');
    img.setAttribute('src',src);
    img.style.width='10%';
    anchor.appendChild(img);
   }
  }

You can add to show the png file by adding in the if condition in the script :

src.indexOf('.png') > -1 || src.indexOf('.PNG') > -1

I hope to help you.

News: Working with python , opengl and ARB ...

Today I test a simple script that uses the OpenGL ARB "Architecture Review Board".
The script is very simple and can be found on my graphic-3d.blogspot.com.
I make this with Python 2.6.4 , pyopengl module.

Fedora online defragmenter for ext4 filesystem

The tool is e4defrag.
The man page tells us: reduces fragmentation of extent based file.
The file targeted by e4defrag is created on ext4 filesystem made with "-O extent" option (see mke2fs(8)). The targeted file gets more contiguous blocks and improves the file access speed.
Let's try this tool.
You can try under root account this:
# e4defrag -test -cv /home/your_user/
The final result on my account is :
Total/best extents 170276/165520 Fragmentation ratio 0.03% Fragmentation score 0.24 [0-30 no problem: 31-55 a little bit fragmented: 55- needs defrag]
Also, you have to run e4defrag with the -test parameter for now, since it isn't a fully tested version.

The LightScribe - without labels and handwriting.

LightScribe is an innovative technology that uses a special disc drive, special media, and label-making software to burn labels directly onto CDs and DVDs.
Download the packages from here.
Use the root account and install this packages :

# rpm -ivh lightscribe-1.18.24.1-linux-2.6-intel.rpm 
Preparing...                ########################################### [100%]
   1:lightscribe            ########################################### [100%]
# rpm -ivh lightscribeApplications-1.18.15.1-linux-2.6-intel.rpm 
Preparing...                ########################################### [100%]
   1:lightscribeApplicationswarning: group admin does not exist - using root%)
warning: group admin does not exist - using root
########################################### [100%]

The path application is /opt/SimpleLabeler/
See the files:

$ ll
total 332
drwxr-xr-x. 4 root wheel   4096 Feb 27 14:10 content
-rwxr-xr-x. 1 root wheel   2980 May 19  2010 launchBrowser.sh
drwxr-xr-x. 3 root wheel   4096 Feb 27 14:10 plugins
-rwxr-xr-x. 1 root wheel     43 May 19  2010 qt.conf
-rw-r--r--. 1 root root      16 May 19  2010 qttr.qm
-rwsr-xr-x. 1 root wheel 314088 May 19  2010 SimpleLabeler
-rw-r--r--. 1 root root      16 May 19  2010 simplelabelertr.qm

Run the SimpleLabeler, and you see this :

Insert the special media in the special disc drive with the face down.
This is a way to not use labels and handwriting.

G'MIC plug-in for GIMP.

GIMP is an acronym for GNU Image Manipulation Program and it has many capabilities.
One best feature is the plugins system. Plugins may be stored in different locations depending upon your distribution.
The author of G'MIC plug-in tell us: The G'MIC plug-in for GIMP proposes a set of various filters to apply on your images, including artistic effects, image denoising, and enhancement algorithms, 3D renderers, etc.. It is a quite large plug-in, integrating a lot of different effects.
You can download the G'MIC plug-in from here.
Unzip the file and go to the folder where is the gmic_gimp file.
Use this command to copy the file in the plug-ins folder.

$ cp  gmic_gimp ~/.gimp-2.6/plug-ins/

Once you have installed the plugin just restart the GIMP.
The G'MIC will work just if you have opened an image.
You can find it on menu: Filters-> G'MIC... Also, the G'MIC plug-in has available 284 filters.

Protect your root account.

I will present a solution to protect the root account, quite funny but still elegant.
You can read about the command trap using: man trap.
What is this command?
when the specified event will occur will execute the command specified.
In this case, it will receive signal respectively will execute one command - exit
The source code.

 protect()
 {
 echo "What is the secret ?"
 trap protect 2 20
 read -s resp
 if [ "$resp" != "asd" ]; then
 echo "Error!"
exit
fi
 }
 protect

The result will be leaving the root account if you do not answer the question correctly.
Now protect the file against unauthorized changes:

# chmod 700 /root/.bashrc

You can create using the example above, different ways to execute various commands.

Android ARM Assembly by Vikram Aggarwal

Today I read an interesting article about Android.
The article is written by the developers Vikram Aggarwal, a software engineer at Google.
This article - tutorial consists of a series on learning ARM assembly on Android.
Its subject is "...calling Assembly code from Android applications".
The tutorial contains the necessary source code and details for the reader to understand how it works.
For those who have never used Gas (GNU Assembler), this article is of interest much.
I wonder if there is anyone interested in the Fedora community to write Android applications.
This article can be read here.

Creating folders and documents with gdata module

Today I played with gdata python module.
The problem that I solved it:
creating folders and documents in your Gmail account.
First, you need to install the gdata module.
In fedora I used:

yum install python-gdata.noarch 

Here are the first lines of source code that creates a folder named test-fedora

Python 2.7.1 (r271:86832, Apr 12 2011, 16:16:18) 
[GCC 4.6.0 20110331 (Red Hat 4.6.0-2)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import gdata.docs.service
>>> my=gdata.docs.service.DocsService()
>>> my.ClientLogin('your-account@gmail.com','your-password')
>>> my.CreateFolder('test-fedora')

I tried to automate the process of creating folders and I used a list and instruction for

>>> folders=['aaa','bbb','ccc']
>>> for f in folders:
...     my.CreateFolder(f)
... 

To create a document to write more lines of code.
This is because there are many types of documents

>>> new_entry = gdata.GDataEntry()
>>> new_entry.title = gdata.atom.Title(text='fedora-test')
>>> category = my._MakeKindCategory(gdata.docs.service.DOCUMENT_LABEL)
>>> new_entry.category.append(category)
>>> created_entry = my.Post(new_entry, '/feeds/documents/private/full')

Here's a simple solution to avoid loss of mail password.

>>> import getpass
>>> username = raw_input('Please enter your username: ')
Please enter your username: user1
>>> password = getpass.getpass()
Password: 
>>> print username
user1
>>> print password
pass1

I hope you will use this

The list of linux tutorials ...

The last time I wrote small tutorial for free-tutorials.org site.
These tutorials have covered several areas.
Here are targeting Linux.
The indication of a denial of service (DoS) attack...
How to display memory in real time on Linux system...
Change settings and passwords in Windows using Lin...
How to change bash custom prompt ?
How to use the import command to take screenshots?
Linux commands : "find" and the option "empty"
Create html file with bash script.
Simple bash script to create folders, files and im...
Using wget tool
error: dd: opening `/dev/sdb1': Permission denied...
error: 'memset' was not declared in this scope
Installing and configuring the Eclipse IDE - Googl...
How to set up an external webrowser on Eclipse IDE
Fedora - Install Skype
Modifying shortcuts keys on Bluefish 1.0.7
Fedora - How we can get movies from youtube.
Fedora 12 - How can we run one script when system ...
Linux Text-To-Speech Tutorial
Geany and regular expressions.
Yumex on Fedora
Assign keys on Linux.
I will try to write more tutorials about Linux...

Fedora 15 : Extracting rar files

The unrar package can be installed from here.
The unRAR utility is a freeware program, distributed with source code and developed for extracting, testing and viewing the contents of archives created with the RAR archiver version 1.50 and above.

unrar-3.9.9-1.fc15.x86_64.rpm  
unrar-3.9.9-1.fc15.i686.rpm  
unrar-3.9.9-1.src.rpm  
unrar.spec

$ unrar

UNRAR 3.92 freeware      Copyright (c) 1993-2010 Alexander Roshal

Usage:     unrar  - -  
               <@listfiles...> 


  e             Extract files to current directory
  l[t,b]        List archive [technical, bare]
  p             Print file to stdout
  t             Test archive files
  v[t,b]        Verbosely list archive [technical,bare]
  x             Extract files with full path


  -             Stop switches scanning
  ad            Append archive name to destination path
  ai            Ignore file attributes
  ap      Set path inside archive
  c-            Disable comments show
  cfg-          Disable read configuration
  cl            Convert names to lower case
  cu            Convert names to upper case
  dh            Open shared files
  ep            Exclude paths from names
  ep3           Expand paths to full including the drive letter
  f             Freshen files
  id[c,d,p,q]   Disable messages
  ierr          Send all messages to stderr
  inul          Disable all messages
  kb            Keep broken extracted files
  n       Include only specified file
  n@            Read file names to include from stdin
  n@      Include files listed in specified list file
  o[+|-]        Set the overwrite mode
  or            Rename files automatically
  ow            Save or restore file owner and group
  p[password]   Set password
  p-            Do not query password
  r             Recurse subdirectories
  sl      Process files with size less than specified
  sm      Process files with size more than specified
  ta      Process files modified after  in YYYYMMDDHHMMSS format
  tb      Process files modified before  in YYYYMMDDHHMMSS format
  tn      Process files newer than 
  to      Process files older than 
  ts[N]  Save or restore file time (modification, creation, access)
  u             Update files
  v             List all volumes
  ver[n]        File version control
  vp            Pause before each volume
  x       Exclude specified file
  x@            Read file names to exclude from stdin
  x@      Exclude files listed in specified list file
  y             Assume Yes on all queries

Works well.

Firefox sync - sinking ?

Today I tried to use Firefox Sync.
I do not remember if I had a user account, but I tried to make a password reset.
I do not know if the same thing happens on Windows, but on Fedora, I received a strange thing output.
I assumed that it is a cookie, but it is not normal.
Maybe someone can tell what it is ...
Here's the picture with this strange number:

The myth of drop_caches

I will try to clarify the myth about drop_caches.
This along with other settings can be made in the folder: /proc/sys/vm/
First, the files in this directory can be used to tune the operation
of the virtual memory (VM) subsystem of the Linux kernel and also to
write out of dirty data to disk.
About drop_caches we can say that is only one of the options and not only make
causes the kernel to drop clean caches, and entries inodes from memory,
the result causing that memory to become free.
We have three basic options :

• to free pagecache: echo 1 > /proc/sys/vm/drop_caches
• to free dentries and inodes: echo 2 > /proc/sys/vm/drop_caches
• to free pagecache, dentries and inodes: echo 3 > /proc/sys/vm/drop_caches

Note that user should run sync first.
What happens then?
The answer is also simple and clear.
If you drop the cache than the CPU load goes up. This happens because the cache is gone.
Also, available RAM goes up because the cache is empty.
Logical, the performance will suffer because you are not taking advantage of the cache.
Then over time, the caches will fill and this is a good thing if you don't instruct Linux to drop the caches.

In reality, dropping caches has a little positive effect on performance, but in fact, it tends to have a negative effect in long-term.
I hope I have correctly understood and explained, so if you think it is not, I wait for your feedback.