Monthly Archives: August 2013

LogExpert. Just a great software!

How are we trac the logs? Go to folder -> open file -> see the logs -> close file -> go to next file and so on.
A long time i use a thing called LogExpert – is a tail analog tool for windows with tabs and sessions support. Also many features exist.
It is very convenient to observe many log files simultaneously!

Really heplful, thanx for developers! You’ve saved my time.

Official website:

Digital Signature explanation

The security is very important concept today for all type of systems. So, we have to know how to protect your data from theft, hijacking, etc.
Encryption is reversible conversion of data to hide payload from other reading.

The are two types of encryption algorithms:
1. Symmetric Encryption (Private-key (or secret-key) cryptography).
Uses the same key for encryption and decryption of message.

2. Asymmetric Encryption (Public-key cryptography).
Uses public key for encryption and private key for decryption of message.


The payload messages usually use digital signature for protection. Explanation of how the digital signature works below in a few steps:

1. Angela wants to send a message to Hugo.


2. Angela request a certificate from Certification Center.


3. Certification Center sends a certificate with public-private key pair.


4. Angela calculates hash of message. Encrypts obtained hash with private key – this is a Digital Signature! And attach DS to message.


5. Angela sends DS, Message and certificate to Hugo.


6. Hugo decrypts digital signature with public key. Take a hash from Message. Then, he checks decrypted value and hash for equality. If values are equal – message is valid and it can be read, otherwise – message is invalid!


See also,

Firefox home page opening in new tab configuration

To configure the firefox browser to open home page when new tab is opening, use next:

1. Type about:config in address bar.
Confirm next dialog:
2. Add new string property (if not exists): browser.startup.homepage with value of your page.
3. Add new string property (if not exists): browser.newtab.url with value of your page.
The default valus is about:newtab

So, you’ll see next:

Thats’s all!

JDK quick install on Ubuntu Linux

Quick reference to install JDK7 on Ubuntu.

1. Download the JDK7 from
2. Create dir and unpack:

sudo mkdir -p  /usr/lib/jvm/
sudo mv java-7-oracle/ /usr/lib/jvm/

3. Get script to change alternatives:


4. Change exec permissions:

chmod 755 ./update-java-0.5b

5. Finally, execute it:


Select your JDK:

To check that’s all ok, use next:

java -version
javac -version