Setting of root password in ubundu(linux)

Ubuntu has no password for root user as default.If you want to reset root password, you need to use sudo passwd command in shell. To Open shell, click Applications » Accessories » Terminal. In shell,type sudo passwd. It will ask you password. Type your login password.
venkat@venkat-desktop:~$ sudo passwd
Password:
And then it will ask you to reset password for root. Type it twice
Enter new UNIX password:
Retype new UNIX password:
After reset root password. It will show this message in Shell(passwd: password updated successfully).

Rails Installation

       Installation of  rails and mysql

step1:Ruby installation:
$sudo apt-get install ruby ruby-dev libopenssl-ruby1.8 irb ri rdoc

Step2:Install Mysql
 if mysql allready installed in your computer give the below command
$sudo apt-get install libmysql-ruby sqlite3

if mysql not install in your computer
$sudo apt-get install mysql-server sqlite3 libmysql-ruby

step3:some header files needs to install for compile
$sudo apt-get install build-essential libmysqlclient-dev libmysql-ruby libsqlite3-ruby libsqlite3-dev

Step4:Need gem install
$sudo apt-get install rubygems

Step5:install mysql,rails,sqlite3-ruby mongrel through rubygems
$ sudo gem install rails mysql sqlite3-ruby mongrel
if this show errors
$sudo apt-get install rails rails-doc rails-ruby1.8
then retry this
$ sudo gem install rails mysql sqlite3-ruby mongrel
Rails successfully install your system..
To check if is install
open terminal
$rails -v
Rails 3.0.3

   if you have any doubt in installation in rails and mysql  go throught the blog
    http://www.coachfactory.blogspot.com/  you can get clear idea about this