Tuesday, July 31, 2012

Install PostgreSQL 9.1.4 on Ubuntu 12.04

To install PostgreSQL 9.1.4

Add already compiled ppa key
$ sudo add-apt-repository ppa:pitti/postgresql

Update you're repo & install postgres
$ sudo apt-get update
$ sudo apt-get install postgresql

Logged as postgres user and create database , user and grant all permission to users for database.

postgres$ psql template1
psql (9.1.4)
Type "help" for help.

For creating user and database, refer this guide

Install Adobe Reader/Flash on Ubuntu 12.04

1. To install Adobe Flash/Reader, enable canonical partner repository by running below command

$ sudo apt-add-repository "deb http://archive.canonical.com/ $(lsb_release -sc) partner"

2. Update the system and install Adobe Flash Player & Adobe Reader

$ sudo apt-get update
$ sudo apt-get install flashplugin-installer acroread

I hope it may helpful to install Adobe Flash Player & Adobe Reader on ubuntu 12.04 without any issues.

Install Adobe AIR on Ubuntu 12.04

1. Download Latest Version Adobe Air for Linux

$ wget http://airdownload.adobe.com/air/lin/download/latest/AdobeAIRInstaller.bin

2. Change the persmission of the file

$ chmod +x ./AdobeAIRInstaller.bin

3. Install Adobe Air

$ sudo ./AdobeAIRInstaller.bin

While installing if you get message about missing gnome-keyring or KDE Wallet, then run the below command to fix it

$ sudo ln -s /usr/lib/i386-linux-gnu/libgnome-keyring.so.0/usr/lib/libgnome-keyring.so.0
$ sudo ln -s /usr/lib/i386-linux-gnu/libgnome-keyring.so.0.2.0/usr/lib/libgnome-keyring.so.0.2.0

For 64-bit systems

$ sudo ln -s /usr/lib/x86_64-linux-gnu/libgnome-keyring.so.0/usr/lib/libgnome-keyring.so.0
$ sudo ln -s /usr/lib/x86_64-linux-gnu/libgnome-keyring.so.0.2.0/usr/lib/libgnome-keyring.so.0.2.0

Re-run installer again

I hope you have successfully installed Adobe Air, In case if your facing any issues let me know.

Monday, July 30, 2012

Google-chrome-stable depends on libnss3-1d (>= 3.12.3); And Google-chrome-stable depends on libxss1;

When you trying to install google chrome on Ubuntu 12.04, you may end up with this error message

$ dkpg -i google-chrome-stable_current_i386.deb

Google-chrome-stable depends on libnss3-1d (>= 3.12.3);  however;
Package libnss3-1d is not installed.
Google-chrome-stable depends on libxss1; however;
Package libxss1 is not installed
dkpg: error processing google-chrome-stable (--install)

To fix this issue you need to install those missing packages. Here are commands to install those packages

$ sudo apt-get install libnss3-1d:i386
$ sudo apt-get install libxss1:i386

Then try

$ dkpg -i google-chrome-stable_current_i386.deb

I hope this time you can able to install Google Chrome without any issues.

Rails 3 - Bundler


Bundler is used to manage your application's gem dependencies. By default all Rails 3 application contains bundler gem.

If your applications need gems other than those belonging to Rails itself, you'll need to specify those gems into manifest file named Gemfile into the root of your Rails project directory.

Simple syntax to load gem

gem "paperclip"
gem "rspec"

Syntax to load gem on specific application environment

group :development, :test do
   gem "rspec"

Syntax to load specific gem version

gem "rspec" , "1.2"
gem "rspec", "> 1.2"

Syntax to load gem form a Git Repository

gem "paperclip", :git => "git://github.com/thoughtbot/paperclip.git"

Installing Gems

Once you update the Gemfile then make sure you have installed all the dependencies in your Gemfile of Rails 3 applications.

$ bundle install
$ bundle install --without test

These commands will install all gem dependencies on your Rails 3 application which is specified on Gemfile.

Packing Gems

You can package up all your gems in the vendor/cache directory inside of your Rails 3 applications.

Here is the syntax to package up

$ bundle package

I hope you have some idea about Bundler and how it helpful in Rails 3 applications. If you need any clarifications please let me know.

Friday, July 27, 2012

Vaadin 6.8.1

Vaadin version 6.8.1 has been released. Here is more details about fixes/changes and downloads


Rails 3.2.7!

Rails Team has been announced version 3.2.7. It contains important security fixes(see here), so update quickly.

Source code & change logs are available here


Tuesday, July 24, 2012

Twemcache - Twitter Memcached

Twitter Open sourced Twemcache, it is based on a fork of Memcached v.1.4.4 that has been heavily modified to make to suitable for the large scale production environment at Twitter.



Iago - Load Generator

Twitter open sourced lago, it help twitter to test services before they encounter production traffic.

Iago supports following formats:

Memcached / Kestrel

Checkout lago source code and more information about it's Architecture/Overview/examples  on GitHub



Install MongoDB on Linux

1. Download the binary and extract it

cd /opt/
sudo wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-2.0.6.tgz
sudo tar -xzf mongodb-linux-x86_64-2.0.6.tgz

2. Create a softlink to you're extracted mongodb content/folder

sudo ln -s mongodb-linux-x86_64-2.0.6 mongodb

3. Create soflinks for mongo binaries

cd /usr/bin
sudo ln -s /opt/mongodb/bin/mongod
sudo ln -s /opt/mongodb/bin/mongo

4. Generally MongoDB save you're database stuff into the directory. So we should create the directory if it doesn't exists

sudo mkdir /data
sudo mkdir /data/db

5. Start the MongoDB Server

sudo mongod

I hope these steps helpful to install MongoDB without any issues, If you have any issues let me know.


Monday, July 23, 2012

Linux Kernel Release - Version 3.5

Linux 3.5 has been released!, Major updates were

1.Major features in Linux 3.5

ext4 metadata checksums
Uprobes: userspace probes
Seccomp-based system call filtering
Bufferbloat fighting: CoDel queue management
TCP connection repair
TCP Early Retransmit
Android-style opportunistic suspend
Btrfs: I/O failure statistics, latency improvements
SCSI over FireWire and USB

2.Driver and architecture-specific changes

3.Various core changes

4.Memory Management






10.File systems

For more information about features and changes