CEntos 6.7 Migrating from mysql-server/mysql-community-server into latest MariaDB

Ok, first you should install yum-replace plugin if you haven’t already have it.

yum install yum-plugin-replace

Get MariaDB packages repo from MariaDB repos builder here
MariaDB repo builder
You’ll get some repo config text that you can save to /etc/yum.repos.d/MariaDb.repo like these:

# MariaDB 10.1 CentOS repository list - created 2016-04-17 23:39 UTC
# http://mariadb.org/mariadb/repositories/
name = MariaDB
baseurl = http://yum.mariadb.org/10.1/centos6-amd64

Do update your repo chache

yum update

If you’re installing mysql-server from CentOS 6.7 default repo, you should do this:

yum replace mysql-libs --replace-with=MariaDB-common

If you’re installing mysql server from webtatic repo (mysql55w-server), you should do this:

yum replace mysql55w-libs --replace-with=MariaDB-common

If you’re installing from MySQL Community repository, do this:

yum replace mysql-community-common --replace-with=MariaDB-common

Just answer with ‘Y’ if the yum replace command show you some conflicts.
Next, just install all MariaDB related packages:

yum install MariaDB-*

Start MariaDB:

/etc/init.d/mysql start

Confirm that you’re using MariaDB:

[root@www ~]# mysql --version
mysql  Ver 15.1 Distrib 10.1.13-MariaDB, for Linux (x86_64) using readline 5.1

Don’t worry, if you have successfully installing MariaDB over MySQL:

  1. your web app that use MySQL will not broken, no need to change anything
  2. your data will stay intact (no data loss)
  3. use MySQL commands as usual (such as: mysql -u root -p)
  4. the MariaDB config is still in /etc/my.cnf

In short, business as usual!

Blogging again?

Well, it seems that auto-post random post to twitter/Fb is working again and I see my old posts.
Not nice and give some burden to post a new one. Maybe I should begin to post something again.

Exporting high resolution image from QGIS project



You want to export your QGIS project into high resolution image. QGIS desktop “Project” –> “Save as Image” only save/export the project into a low resolution image (i.e. your desktop resolution).



1. Finish your project in QGIS

Finish your GIS project in QGIS Desktop, choose which layers to be shown, what style should it use, etc.

2. Choose your extent that will be exported into image

For myself, I choose the full-extent, but you may choose the extent as you wish. You my use “Vector” –> “Coordinate Capture” to help copying the coordinates. You will need to write down the coordinates for [xMin, yMin] (top-left coordinate) and for [xMax, yMax] (bottom-right coordinate). Save and close your QGIS project.

3. Execute the export command via command line of QGIS

Open your command prompt/console (preferably as Administrator/root). Go to your QGIS binary folder, where you install QGIS +”bin” folder, for example C:\Program Files\QGIS Brighton\bin. Use this command template:

qgis --project "c:\where\you\save\your\qgis\project\file.qgs" --snapshot "c:\where\you\want\to\save\your\image.png" --height result_image_height --width result_image_width --extent xmin,ymin,xmax,ymax

For example:

C:\Program Files\QGIS Brighton\bin>qgis --project "D:\work\dita s1\pmapper\Semarang\Kec_Banyumanik\banyumanik.qgs" --snapshot "c:\users\achmadz\documents\padangsari.png" --height 5000 --width 5000 --extent 435825.86153,9218725.47861,438150.22840,9217277.65534

That command will open QGIS Desktop for a moment then close itself. The command will produce padangsari.png in c:\users\achmadz\documents\. Open the image, and you’ll see the image in high resolution (5000×5000 pixels).


Windows Installer Cleaner

Some background:

My SSD drive is almost full, after checking with TreeSize Free, it seems a lot of space is taken by files inside c:\windows\installer\. Searching around, I conclude that some of files is safe to be deleted from that particular place. There is a VB script inย http://blogs.msdn.com/b/heaths/archive/2007/01/31/how-to-safely-delete-orphaned-patches.aspx that detect which files that shouldn’t be deleted from c:\windows\installer.

I also know an application named WiCleanup from KZTechs that detect and delete the “safe” files but after I tried it, the confirmation of deletion for files one-by-one makes me uncomfortable. So, I decide, why not programming the application by myself? And this application is born!


I programmed the application in VB .NET language using the free Microsoft Visual Studio 2013 Community Edition. Without further a do, you can download the application here:

[button link=”http://www.ahowto.net/wp-content/uploads/2015/03/Release.zip”]Windows Installer Cleaner Binary Only[/button]
(Of course you need .NET framework 4.5 installed if you want to run this application)
[button link=”http://www.ahowto.net/wp-content/uploads/2015/03/wic_winform.zip”]Windows Installer Cleaner Full Source Code[/button]

How to use:

It’s quite straight forward. There are three buttons there, you just need to click on them sequentially.

  1. Click “Get Kept List” to see which files that you should keep on c:\windows\installer
  2. Click “Get Delete List” to get the files that should be safe to be deleted and their size.
  3. Click “Delete Files” to delete the detected files.

What I learn from building this application:

  • how to create .NET application that need Administrator privilege (UAC things) when executed
  • how to use COM object in .NET application
  • how to use/import .dll from MS Windows in .NET
  • some file operation in .NET (FileInfo, deleting files, file’s attribute)
Windows Installer Cleaner Screenshot in Windows 7 64-bit

Windows Installer Cleaner Screenshot in Windows 7 64-bit

The application is already tested on Windows 8.1 64-bit and Windows 7 SP1 64-bit. Both systems is running fine until now. ๐Ÿ˜€

Using linkbucks API / posting data using cURL in PHP



  • Register to linkbucks if you don’t have any account there (it’s free and you probably should use email other than gmail and hotmail if you want quick confirmation from linkbucks)
  • Find your username and API password from your profile page: https://www.linkbucks.com/Profile/ . If your API password is empty, just click “Reset API Password” link to show it.

This is our little PHP function that help us to POST data to certain URL:

//function to POST data using cURL in PHP
function curl_post($url, $data, $ip="", $ref="", $ua="") {
    //initiate cURL
    //set referer only if stated by user
    if ($ref!="") {
        curl_setopt($ch, CURLOPT_REFERER, $ref);
    //set IP interface if needed (for multi-IP server)
    if ($ip!="") {
        curl_setopt($ch, CURLOPT_INTERFACE, $ip);
    //set user agent if stated by user
    if ($ua!="") {
        curl_setopt($ch, CURLOPT_USERAGENT, $ua);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

    return $response;

How to use it to call linkbucks API:

    'user'=>'chmdznr',  //my username
    'apiPassword'=>'d55ae4eaf97b445f',  //my API password
    "originalLink"=>"http://google.com",  //the URL that need to be shorted
    "adType"=>2,  //paid links
    "contentType"=>1,   //not an adult content
    "domain"=>"yyv.co"  //target domain, a lot of possibility here, the default is: linkbucks.com 

//call linkbucks API

$returned_data=curl_post($url, json_encode($data_kirim));

//simple error checking
if (!empty($parsed_data->link)) {
    echo "This is your short URL : ".$parsed_data->link;
} else {
    echo "Something wrong! ".$parsed_data->errorDescription;

The curl_post function is quite generic, you can use it to send data to remote URL using POST method like this:


$returned_data=curl_post($target_url, http_build_query($login_data));

You should notice that the data array need to be converted using http_build_query first (in linkbucks’ case, it doesn’t need to be converted first).
You can also add more advanced feature in the function such as handling the timeout and cookie.