prob in installing new appln.

[Zill]

spibou: Apart from the problems of version control and "dependency hell" when installing from source, the other main problem is that the apt package management system does not "know" about software installed by other methods.

As Ubuntu has periodic security updates for packages, the lack of version control with compiled software, and its dependencies, means that these can get out of sync with the packaged applications. This can lead to various problems, including system breakage.

I accept that it may be possible for an experienced user to resolve these problems, but IMHO this will be quite daunting to a newbie.

[spibou]

Can you give a specific scenario of how it would lead to system breakage?

[teddks]

Can you give a specific scenario of how it would lead to system breakage?

If you installed (through source, manually) a library which another application uses, then changes in that library could cause breakage in those applications.

It's also a huge b**ch to get some things to compile; but these things tend to be quite essential. It's much easier just to use the package manager, and in most cases, you should be able to. When you can't, installing something from source is usually just

1. download the source tarball from the distribution site
2. extract sources
3. in terminal, cd into the source directory and

4. ./configure && make && sudo make install

./configure invokes a shell script which gets the build environment ready for building, make compiles the application, and sudo make install installs it. Before compiling anything, you'll need to install the 'build-essential' package.

[Zill]

...If you installed (through source, manually) a library which another application uses, then changes in that library could cause breakage in those applications...

Agreed!

[arunprasad13]

I owe you a great debt of gratitude for explaining me the concepts to such depth.thanks buddies.

[teddks]

No it isn't. How did you get that idea?

This sounds like FUD to me, how would he break his system?

Installing things from source packages is an instance of using the "your memory" package manager. You remember what versions of everything you have installed, and remember to go cruise to the sites to check for updates. Every time you want to install something, you need to go hunt down the dependencies, and hunt down their dependencies, and so on, until you build the full dependency tree. You also have to check every other thing that depends on any dependencies you'd be updating to see if they'd break if a newer version of a library was installed.

By contrast, the default package manager in Ubuntu is Apt. It does all of that for you, and it can't forget. The downside is that you have to rely on the repositories for programs, so sometimes you aren't running bleeding-edge. You are, however, always running stable, tested code.

Hence, the "your memory" package manager is deprecated in favor of Apt, as it is far, far better.

How would you break your system?

1. You install version 0.9.3 of libfoo. Program bar depends on .9.2 of libfoo, and breaks when you install 9.3.
2. You install version x.y.z of a critical system package. It breaks everything by not having interoperability with the other parts of your system.

The benefit of using Apt is that all of these breakages are tested for.