Studying for LPIC... Need RPM help.
 

I need something explained. What is the purpose of rebuilding an rpm from source code?

The way I understand is, the only reason you need to rebuild an rpm from source code is if you have migrated an rpm from one dist of linux to a different one, which resulted in dependency problems.

Another thing, is "building a binary package from source" the same as "rebuilding a package from source"?

Can anyone let me know if I have the right idea?

many reasons to use "rpmbuild" to convert a standard source build into a rpm package

the main is
" the office"
a custom update needs to be pushed to the 50 + RHEL6 machines in the office

you build the custom code
Turn it into a RPM with a higher version number
move it to the local software repo
and let the office machines auto install it on the normal everyday update check

or other reasons
an example
I have been building the program " The Gimp " since 2001
it is right now just an old habit
but replacing the OpenSUSE version with MINE
has issues
the rpm dependencies in the database are "out of wack"

some programs NEED the gimp development code installed
( the SAME CODE i built from source )
so turning it into a rpm i can use the package manager to install MY build of it
and keep the package manager happy by NOT having missing dependencies
and NOT having the package manager AUTO reinstall the OS version of the program over the VERSION I BUILT .

So that custom code you build for the new update, is that code built from the previous versions source code, with some changes made? (and the updated version number)?

As far as the Gimp example. So you are taking a program that already existed on OpenSUSE and you are changing the code, and I assume creating new config files/libraries and such. Which you then build into an rpm package that has the same name as the old gimp program but a higher version number? I assume thats how you prevent the reinstallation of the original package?
Sorry if I am way off...

My own example, compiled the kernel module for a b43 driver not included in centos. I have 5 systems with that wireless card and don't want to always compile the kernel module, so an rpm is quick and easy.

post #3 is about right

now you do not HAVE TO do that.
But once you bass say 3 or 4 DEFAULT installed programs or common ones it gets VERY VERY complicated
locking out rpm's you do NOT want to be installed

so making sure that the rpm database is CORRECT is VERY NICE and a very GOOD idea

but
you do not HAVE TOO , it is just a very good idea too do that .