Category: Technical

  • SQL JOINS quick tutorial

    Table T1, Table T2

    INNER JOIN returns only matching rows from T1, T2

    LEFT OUTER JOIN returns (all T1 rows) X (matching T1 rows in T2)

    RIGHT OUTER JOIN returns (all T2 rows) X (matching T2 rows in T1)

    UNION returns only unique rows from T1, and T2.

    UNION ALL returns T1+T2 rows

  • https in 5 easy steps

    Simple 5 step guide to setting up https with your own self-signed certificate
    Prerequisites: Apache2, Ubuntu Server

    1. Generate local keypair
      /usr/bin/openssl genrsa -des3 -out {your domain name}.key 3072
    2. Create self-signed certificate
      /usr/bin/openssl req -new -key {your domain name}.key -x509 -out {your domain name}.crt

    3. Configure your host on port 443 to use the certificate
      <VirtualHost {your ip}:443>
      ...
      SSLEngine on
      SSLCertificateFile {path where certificate is}/{your domain name}.crt
      SSLCertificateKeyFile {path where key file is}/{your domain name}.key

      SetEnvIf User-Agent ".*MSIE.*" nokeepalive ssl-unclean-shutdown
      ...
      </VirtualHost>
    4. Optional: If you do not want to enter key password each you restart Apache, you can embed the password in key itself.
      /usr/bin/openssl rsa -in
      {path where key file is}/{your domain name}.key -out {path where key file is}/{your domain name}.key.nopass
      Remember to update your Apache configuration to use the new file
      # SSLCertificateKeyFile {path where key fileis}/{your domain name}.key
      SSLCertificateKeyFile {path where key file is}/{your domain name}.key.nopass
    5. That’s it view it. Restart your apache to load the new configuration. And try accessing your url with https://

    If you receive a certificate warning, simply accept it, and proceed. Congratulations, your communication is now encrypted, and safe from prying eyes!

    Self-signed certificate

  • Colors to your life

    Very often we are impressed with awe when we see a beautiful picture, photo, advert. The colors, their combination presents an alluring view just right for our eyes. If you notice more closer, you can seeing that more often the colors are complemented (red with white, green with blue…) to give a undistracted overall look. This is essentially because our eyes find this visually pleasant.

    I have a tool which can offer such combinations, and you should design your color combinations using the suggested patterns

    http://9i9.me/colors/index.html/ – For visually stunning color combinations

    Keep working!

  • Secretmyth BDRips – audio/video out of sync

    More recently, all Secretmyth BDRips I download started to have a audio out of sync with video issue. Real sad, because the movie quality is too good when watching on a 24 inch screen. I use K-Lite, but it seems SecretMyth recommends either KMPlayer or VLC.

    The problem solved using VLC.

  • Interesting alternatives to databases in opensource

    I stumbled upon this url. The list of various options on databases is pretty amazing.

    http://www.webresourcesdepot.com/25-alternative-open-source-databases-engines/

    It’s a definite read. I never knew so many existed.

  • How to manually uninstall Symantec Endpoint Protection client from Windows 2000, XP and 2003, 32-bit Editions

    Much recently to my dismay, I figured out that I cannot remove Symantec’s Endpoint Protection from my own laptop without administrator password. I do not own this password, and I do not want anybody other than me permitting me what to uninstall. Hence I went ahead for manual uninstall according to these instructions (from Symantec’s own site) below-

    How to manually uninstall Symantec Endpoint Protection client from Windows 2000, XP and 2003, 32-bit Editions.

    The instructions are crisp and clear. I could manually uninstall following each step of those instructions, but there is one big trouble. The instructions talk to removing over 100’s of registry keys, values which I believe is sheer impossible manually. Why didn’t Symantec simply provide a small tool which has all those instructions bundled in a simple click-n-go fashion?

    I have tried to create a small registry file which can automate the removal of registry entries Uninstall Registry entries for Symantec Endpoint Protection
    For all other manual deletion of files, it would be great to write a small AutoIt script compiled to an exe. Maybe sometime later…

  • Tortoise SVN About dialog

    Crazy stuff people do these days.
    Photobucket

  • Wikimedia Downloads

    Wikimedia Downloads

    The following kinds of downloads are available:

    Database backup dumps
    A complete copy of all Wikimedia wikis, in the form of wikitext source and metadata embedded in XML. A number of raw database tables in SQL form are also available.
    Static HTML dumps
    A copy of all pages from all Wikipedia wikis, in HTML form.
    DVD distributions
    Available for some Wikipedia editions.

    Wikimedia Downloads.

  • SSH : Forwarded connection refused by server: Administratively prohibited [open failed]

    Change localhost to 127.0.0.1 and it should work. 🙂

    If that doesn’t solve it, problem might be in sshd_config or authorized_keys2 – Metawerx Wiki: SSHTunnelTroubleshooting.

  • Solr replication

    1)On solr.master:
    +Edit scripts.conf:
    solr_hostname=localhost
    solr_port=8983
    rsyncd_port=18983
    +Enable and start rsync:
    rsyncd-enable; rsyncd-start
    +Run snapshooter:
    snapshooter
    After running this, you should be able to see a new folder named snapshot.*
    in data/index folder.
    You can can solrconfig.xml to trigger snapshooter after a commit or
    optimise.
    
    2) On slave:
    +Edit scripts.conf:
    solr_hostname=solr.master
    solr_port=8986
    rsyncd_port=18986
    data_dir=
    webapp_name=solr
    master_host=localhost
    master_data_dir=$MASTER_SOLR_HOME/data/
    master_status_dir=$MASTER_SOLR_HOME/logs/clients/
    +Run snappuller:
    snappuller -P 18983
    +Run snapinstaller:
    snapinstaller
    
    You should setup crontab to run snappuller and snapinstaller periodically.

    Re: Solr replication.