Install VNC Server on CentOS

First install vncserver as user root

#yum install vnc-server

then add user who runs vncserver
#adduser vncuser

Now setup VNC Password for this user

#su - vncuser
vncserver

It ask password 2 times. You need this password to connect with VNC Viewer.

Now kill the VNC Server

$vncserver -kill :1

:1 is display number. Mostly it will be 1.

Type exit to go back to root shell.

Now edit /etc/sysconfig/vncservers

#vi /etc/sysconfig/vncservers

Add following content to the file, save and exit.

VNCSERVERS="1:vncuser"
VNCSERVERARGS[1]="-geometry 1024x768"

Now start VNC Server

# service vncserver start

Now you will be able to connect to the server with SERVER-IP:1

To start VNC Server on boot

#chkconfig vncserver on

Installing PostgreSQL 9.1 on Ubuntu 11.04

first install python-software-properties:
sudo apt-get install python-software-properties

now add repository and update apt.
sudo add-apt-repository ppa:pitti/postgresql
sudo apt-get update

now instal postgresql
sudo apt-get install postgresql-9.1 libpq-dev

Now change the postgres user password (still running as root):
su postgres
psql -d postgres -U postgres
alter user postgres with password 'a';
\q

To install GUI client pgsql
sudo apt-get install pgadmin3

Install Ubuntu Desktop on Ubuntu server 11.04

First you nee to make sure you have enabled Universe and multiverse repositories in /etc/apt/sources.list file once you have enable you need to use the following command to install GUI

sudo apt-get update

sudo apt-get install ubuntu-desktop

The above command will install GNOME desktop

If you wan to install a graphical desktop manager without some of the desktop addons like Evolution and OpenOffice, but continue to use the server flavor kernel use the following command

sudo apt-get install --no-install-recommends ubuntu-desktop

If you want to install light weight desktop install xfce using the following command

sudo apt-get install xubuntu-desktop

If you want to install KDE desktop use the following command

sudo apt-get install kubuntu-desktop

Install Sun java 6 jre/jdk from PPA in Ubuntu 11.04

Sun Java packages for Ubuntu 11.04 Natty has not yet available in the official repository. However, there’s an easy way to get sun-java-jre, sun-java-jdk, and sun-java-jre-plugin by adding a third-party ppa.

Open up a terminal window under Application -> Accessories -> Terminal, adding the ppa by:

sudo add-apt-repository ppa:ferramroberto/java
sudo apt-get update

Then, install java jre:

sudo apt-get install sun-java6-jre sun-java6-jre-plugin


Install Jdk by the command:

sudo apt-get install sun-java6-jdk

Now check java version

java -version

Installation and configuration of Postgresql 9 server on Centos 6

1. download the postgresql sever bin file.

2. make the binary file executable.

#chmod +x  postgresql-9.1-..bin

#./postgresql-9.1-..bin

3. Now edit pg_hba.conf file and postgresql.conf file to make postgresql database accessable from network.

Go to postgresql folder and search pg_hba.conf under data directory.

#vi pg_hba.conf

Under the line ip4 local connections change as follows

Host      all   all     0/0    md5

Go to postgresql folder and search for posgtresql.conf under data directory.

Under line connection strings make sure the following is true

Listen_address =`*’

Here you can also change the port to which you can connect postgresql DB.

Installation of Jboss 6.1 Server on Centos 6

JBoss Application Server (or JBoss AS) is an open-source Java EE-based application server.

1Download and Install the Java Development Kit (JDK)

i.Downoad Latest version of JDK and move it to /opt directory.

ii.Create the  directory /usr/java and install the JDCK from here.

 Go to /usr/java  and

#chmod +x /opt/jdk-6u26-linux-..bin

#./ jdk-6u26-linux-..bin

2.Download and Install Jboss.

    First download jboss and then  Put jboss directory to /usr/share

3: Create the user, jboss, who will own and run JBoss

# groupadd jboss 

# useradd -s /bin/bash -g jboss jboss 

Change ownership of the JBoss home directory, /usr/share/jboss-6.0.0.Final so all files are owned by the user jboss we created.

# chown -Rf jboss.jboss /usr/share/jboss-6.1.0.Final/ 

 Set the required JAVA_HOME and JBOSS_HOME paths

i.go to jboss home folder

#cd /home/jboss

ii.List the Directory

#ls –a

iii.Open .bash_profile file and add the following to the file

JAVA_HOME=/usr/java/jdk1.6.0_26 

export JAVA_HOME 

PATH=$JAVA_HOME/bin:$PATH 

export PATH 

JBOSS_HOME=/usr/share/jboss-6.1.0.Final 

export JBOSS_HOME 

To check

#su jboss

#echo $JAVA_HOME.This should display following

/usr/java/jdk1.6.0_26

#  echo $JBOSS_HOME  This should display following

/usr/share/jboss-6.0.0.Final 

 Create a start/stop/restart script for JBoss.

i.Copy existing script to /etc/init.d

#cd /usr/share/jboss-6.1/bin

#cp jboss_init_redhat.sh /etc/init.d/jboss

Now go to /etc/init.d

Open jboss and add followings

i.Add lines 3,4, and 5:

# description: JBoss Start Stop Restart

# processname: jboss

# chkconfig: 2345 20 80

ii.Set the JBOSS_HOME to where we unpacked JBoss.

JBOSS_HOME=${JBOSS_HOME:-"/usr/share/jboss-6.0.0.Final"}

iii.Set the JAVA_HOME to where we installed the JDK.

JAVAPTH=${JAVAPTH:-"/usr/java/jdk1.6.0_26"}

iv. Add line 34, which sets the JBOSS_HOST to 0.0.0.0, allowing JBoss to bind to any IP.

JBOSS_HOST="0.0.0.0"

       (Just aboce JBOSS_BIND_ADDR)

Run JBoss as a Service.

Go to /etc/init.d

#chmod 755 jboss 

#chkconfig --add jboss 

#chkconfig --level 234 jboss on 

#service jboss start

Jboss takes some times to start.

Now access Jboss server on browser.

http://localhost:8080

The default username and password is admin admin

The default username and password can be changed by editing

 /usr/share/jboss-6.1.0.Final/server/default/conf/props  file.

Installing LAMP on Ubuntu 11.0

LAMP (Linux Apache Mysql and Php) is one of the most popular web component for a web server.
In this tutorial we will learn to install LAMP on ubuntu server(most popular server for web hosting).

1.Install Apache Web server.
  apt-get install apache2
  now test it on your browser by typing http://localhost or http://ip-address

2.Install Mysql server
  apt-get mysql-server mysql-client
  Upon installing you have to provide the root password.

3.Install PHP
  install php5 libapache2-mod-php5

4.Now Restart Apache
 /etc/init.d/apache2 restart

5.Make Apache and Mysql start on boot
  i.chkconfig --level 235 mysql on
  ii.chkconfig --level 235 apache2 on

6.Now test for Php installation.
 i.create a file called info.php on /var/www
 vi /var/www/info.php

copy the following lines.
<?php
phpinfo();
?>

ii.Open your browser and type http://localhost/info.php
 it should shows the information of installed php installaion

Installing Webmin on CentOS 5.5 Tutorial

Webmin is a web-based interface for system administration for Unix and Linux based Systems. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely.

Installing Webmin on CentOS 5.5 Tutorial
1.First install the GPG key with which the packages are signed

    # rpm --import http://www.webmin.com/jcameron-key.asc

2.Add the Webmin YUM Repository

  # vi /etc/yum.repos.d/webmin.repo
Copy and paste the following lines.

[Webmin]
name=Webmin Distribution Neutral
baseurl=http://download.webmin.com/download/yum
enabled=1

3.Now to install Webmin

    # yum install webmin

Finally browse to your machine on port 10000

https://localhost.localdomain:10000/
as root with your root password.

Install MySQL 5.5.15 on Fedora 15/14, CentOS/Red Hat (RHEL) 5.6/6

Mysql is one of the most populor open source Relational database management system.

1. Change root user
su -
## OR ##
sudo -i

2. Install Remi repository
## Remi Dependency on CentOS 5 and Red Hat (RHEL) 5 ##
rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm

## CentOS 5 and Red Hat (RHEL) 5 ##
rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-5.rpm

3. Check Available MySQL versions

yum --enablerepo=remi,remi-test list mysql mysql-server

4. Update or Install MySQL 5.5.15

yum --enablerepo=remi install mysql mysql-server

5. Start MySQL server and autostart MySQL on boot

/etc/init.d/mysqld start
## OR ##
service mysqld start

chkconfig --levels 235 mysqld on

6. MySQL Secure Installation

    * Set (Change) root password
    * Remove anonymous users
    * Disallow root login remotely
    * Remove test database and access to it
    * Reload privilege tables

Start MySQL Secure Installation with following command

/usr/bin/mysql_secure_installation

By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

Remove anonymous users? [Y/n] Y
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

Disallow root login remotely? [Y/n] Y
 ... Success!

By default, MySQL comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

Remove test database and access to it? [Y/n] Y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

Reload privilege tables now? [Y/n] Y
 ... Success!



Note: If you don’t want some reason, do a “MySQL Secure Installation” then at least it’s very important to change the root user’s password

mysqladmin -u root password [your_password_here]

## Example ##
mysqladmin -u root password myownsecrectpass

7. Connect to MySQL database (localhost) with password

mysql -u root -p

## OR ##
mysql -h localhost -u root -p

8. Create Database, Create MySQL User and Enable Remote Connections to MySQL Database

This example uses following parameters:

    * DB_NAME = testdb
    * USER_NAME = test_user
    * REMOTE_IP = 10.1.1.35
    * PASSWORD = password
    * PERMISSIONS = ALL

## CREATE DATABASE ##
mysql> CREATE DATABASE testdb;

## CREATE USER ##
mysql> CREATE USER 'test_user'@'10.1.1.35' IDENTIFIED BY 'password';

## GRANT PERMISSIONS ##
mysql> GRANT ALL ON testdb.* TO test_user@'10.1.1.35';

##  FLUSH PRIVILEGES, Tell the server TO reload the GRANT TABLES  ##
mysql> FLUSH PRIVILEGES;

Enable Remote Connection to MySQL Server –> Open MySQL Port (3306) on Iptables Firewall (as root user again)

1. Edit /etc/sysconfig/iptables file:

nano -w /etc/sysconfig/iptables

2. Add following line before COMMIT:

-A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT

3. Restart Iptables Firewall:

service iptables restart
## OR ##
/etc/init.d/iptables restart

4. Test remote connection:

mysql -h dbserver_name_or_ip_address -u test_user -p testdb

Installing LCMP stack on CentOS 5.5

Here is the short tutorial about installing lcmp(linux cherokee mysql php pearl) stack.herokee is a high-performance web server. It is very fast, flexible and easy to configure.

1.First install repository for the packages.
# rpm -Uhv http://apt.sw.be/redhat/el5/en/i386/rpmforge/RPMS/rpmforge-release-0.3.6-1.el5.rf.i386.rpm
# rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm
# rpm -Uvh http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/i386/ius-release-1.0-6.ius.el5.noarch.rpm

2.Install Cherokee web server and RRDtool (allows for graphs on the vhosts)
# yum install cherokee
# yum install rrdtool

3.Install MySQL server
# yum install mysql mysql-server

4.Install PHP, Perl and Python.
# yum install php53u-pear php53u php53u-cli php53u-common php53u-devel php53u-gd php53u-mbstring php53u-mcrypt php53u-mysql php53u-pdo php53u-soap php53u-xml php53u-xmlrpc php53u-bcmath php53u-pecl-apc php53u-pecl-memcache php53u-snmp

5.Now for the service to automatically on boot do follow
# chkconfig cherokee on
# chkconfig mysqld on

6.Start mysql and cherokee
# service mysqld start
# service cherokee start

7.Now test php setting
# vi /var/www/cherokee/phpinfo.php
copy and paste following: 

<?php
 // Show all information, defaults to INFO_ALL
phpinfo();
 // Show just the module information.
// phpinfo(8) yields identical results.
phpinfo(INFO_MODULES);
 ?>

8.Start cherokee admin panel
# cherokee-admin -b

9.Now login to http://localhost:9090/.Enter username and password from command prompt.

10.Click vservers.on directory indexes put index.php

11.Click Behavior tab>Default>New>Languages.select php.Click add>create.

 
12.Now click to save the setting and restart cherokee server.

13.Now go to http://localhost/phpinfo.php you should see the php info page.

Basic Linux commands

man [command] : manual for every available command.

    eg: man mkdir display the detail manual about mkdir command.
    Enter q to exit from manual page.
cd : to change current directory.
cp : copy files and directories from one location to another
rm : delete files and directories
mv : move files and directories to another location.
grep: search and find contents of a file within terminal.
cat: display the contents of the file on terminal.
pwd: display current working directory
ls: list the content of files and directories of current directory
top: display processor activity in real time
ps: display process status
kill: terminate process
df -h: display the current partition of your hard drive including size of partiton.

Pidgin

Pidgin is an open source IM application. You can access multiple services with it.
To install pidgin type on command prompt:

apt-get pidgin(debian)
yum install pidgin(fedora)
 

Skype API plugin

To install skype plugin

Download it 

wget http://eion.robbmob.com/skype4pidgin.deb
sudo dpkg -i skype4pidgin.deb

Install festival plugin for Pidgin to text to voice conversion.
 

sudo apt-get install pidgin-festival
Activate and configure Festival plugin
start pidgin.go to tools>plugins and select festival.

Make apt-get Installations and Upgrades 26x faster with apt-fast

There is tweak to fast installation of updates on debian based os.
Steps

1.Install axel download accelerator.
 

sudo apt-get install axel
 

2.Install apt-fast
 

sudo add-apt-repository ppa:tldm217/tahutek.net
sudo apt-get update
sudo apt-get install apt-fast
 

3.Use apt-fast
 

apt-fast install packagename
eg:apt-fast upgrade