Installing Your Favorite Apps

PCQLinux 2008 Core was built from scratch to have a minimal installer and

installed footprint so as to be a powerful host system for running virtual

appliances that we've provided. However, you can also use Core as a fully

capable workstation as well. Although the system comes with a basic set of

applications; you might want to add a number of others on top of it as well.

There are many ways you can do this.

Tech Primer

This distribution is based on CentOS 5.1. Therefore it shares the same

installer technology as the original-which is the RPM format. RPM stands for

RedHat Package Manager after the creators of this packaging method.

Using RPMs has an advantage over the normal way of installing apps on

Linux-that of downloading and compiling source code to get the binary

application. RPMs have all the required files pre-compiled and all it requires

to do is place them in the correct location.

One major issue with using RPMs however is that of dependencies. Many RPMs

depend on other RPMs for certain functionality. If they do not find those RPMs,

you need to install them first before installing the app you want. In case those

RPMs further depend on more RPMs, you again need to find and install them even

earlier. This can sometimes lead to a long drawn process where a user will need

to track down a large number of dependencies and sub-dependencies to many levels

before his application can get installed.

Add/remove programs

In case you are running the graphical interface, you can very easily use the

Add/Remove Program applet available in the Applications menu on the screen. When

you click on this applet (see screenshots on next page), it will get a list of

applications installed on your system as well as a number of applications that

are available on the Internet. Obviously, for this to work, your system must be

connected to the Internet.

When you get a list of applications, these are categorized under different

groups. For instance, you will have applications under groups like Productivity,

Games, System Tools, Development, etc. Browse to the group you wish. You will

then see a list of applications that are available under this group. Ones that

are already installed will have a tick mark next to them while the others can be

downloaded and installed. Simply select the one that you wish to install.

The great part about the Add/Remove Programs applet is that it automatically

resolves all dependencies of the main application you selected. Which means that

you do not need to spend time tracking down other elusive RPMs to get your

application installed. The applet even lets you review the list of dependencies

it finds. Once the applet downloads all the required RPMs, the installation

process starts and the RPMs are installed in the order of dependency. When the

installation is completed, you are informed about the status and then you can

start using the application immediately.

You can view details of the software in each category and select the ones you wish to install or remove by checking or unchecking them

Using Yum installer

Yum is the command line version of the software installer and has a number of

other options as well. You can download new applications from a variety of

places on the Internet. We have already provided you with a huge number of

repositories out of the box in PCQLinux 2008. To install a new application, you

need to simply give the command: yum install name>

For instance, if you want to install The Gimp, you will give the command:

yum install gimp

This will download the headers from all the repositories and calculate the

dependencies and inform you. You can then choose to continue with the

installation or not. You can also update an already installed application to the

latest version by giving the following command: yum update





For instance: yum update gimp

If you wish to remove an application and its dependencies (as long as that

dependency is not also used by any other installed application), you can give

the command: yum remove



If you want to add more repositories to the list of places where you can
download applications from, go to /etc/yum.repos.d and create a new file with

the extension of .repo having the following format:



<>


name=


mirrorlist=


#baseurl=


gpgcheck=<0 or 1>


enabled=1


gpgkey=

In this, you can use either the mirrorlist or the baseurl value. You can also

choose whether to do a GPG check on the downloaded RPMs or not. For instance,

the following adds the Livna repository to the system:

Run the Add/Remove programs applet and you would get a dialog box that shows categorized views of available and installed software

name=Livna for PCQLinux 2008


mirrorlist=http://rpm.livna.org/mirrorlist-7


enabled=1


gpgcheck=1


gpgkey=http://rpm.livna.org/rpm-gpg/RPM-GPG-KEY-livna

You can now use this repository to download files as well.

Installing with RPM



As a final resort, if you cannot do an automatic download and install of

your application (as it is not available in a repository), you can download RPMs

if they are available and install them manually. For this you can either double

click the RPM file in the File Explorer or open a terminal window and enter the

following command: rpm —ivh



For instance, to install the OpenOffice RPMs given on the PCQLinux 2008
Appliances DVD, mount the DVD, browse to the OpenOffice directory and give the

following command: rpm —ivh *.rpm

Within a given set of RPMs, the rpm command can also find the dependencies

and install them in the correct order. However, if it does not find a file that

resolves a dependency, it will fail and exit. In which case you will need to

track down the correct RPM and install it yourself.