info:: Introduction to RPMs

[twistedcranium]

A few of you reading this will equate 'RPM' with vinyl discs that you played on your phonograph or turntable.....but in the Linux world, RPM is a package management program that helps ease the program installation process.

Now RPM is not the only method of installing programs in Linux, and some distributions use other package managers.

To explain how RPMs work, let's consider a ficticious product called "twisted web browser 1.0".

When the developers code the twisted web browser for linux, they have to include not only the executables that make the browser functions run, but they often have to include libraries and other executables that run the graphical user interface or other necessary external features to make the program complete. So let's say the twisted browser uses the Mozilla Gecko arcitecture underneath to handle the browsing functions and some Gnome development kit items to paint the gui that you see, and then attaches those to the main twisted browser executable.

Now, in order for you to run the twisted browser on your system the Gecko and Gnome stuff would need to be there....hence a 'dependency'. So Gecko and Gnome would be dependencies for the twisted browser.

Also, certian distribution libraries or files specifially made for that distribution need to be included....this situation makes some RPMs specific to a distribution of Linux.

So now the developers of the twisted browser compile their program and release it for Red Hat 7.3.

You grab a copy of this RPM and install it using the RPM command.

This RPM, if built properly, looks at your system, determines first if you have permissions to install (root), checks to ensure that you have Gecko and Gnome stuff available and then installs if everything is in order. If the Gecko stuff doesn't exist, it will not install and warn you that you need this.

Packages can be uninstalled using the RPM command as well, but if another program is dependent upon the program that you are trying to uninstall, it won't let you uninstall it.

Now there are many options you can use for the RPM command, such as forcing a program to install and ignoring any dependencies, updating a program to a newer version, obtain a list of installed packages, and query an RPMN package to find out what is in it before you install.

I didn't mean for this to be a comprehensive RPM explanation, but only a mini-info session to help you understand what an RPM package is and to give you enough background to open the RPM man page and dig in!