[SOLVED] understanding Debian package tools??

since1992trying · 08-13-2010, 01:59 PM

I am trying to understanding what happens when a package is installed. It makes me wonder when apt tools remove my packages.

Code:

# apt-get install inetutils-inetd
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages will be REMOVED:
  xinetd
The following NEW packages will be installed:
  inetutils-inetd
0 upgraded, 1 newly installed, 1 to remove and 3 not upgraded.
Need to get 112kB of archives.
After this operation, 172kB disk space will be freed.
Do you want to continue [Y/n]? n

In what cases, "apt-get install pkg" or "aptitude install pkg" command will remove installed packages? If this existing package were removed, how my system runs fine when one of applications need this removed package? Thank you.

AlucardZero · 08-13-2010, 02:27 PM

You are installing a package which does the same thing as another. Only one can exist on a system at the same time.

Code:

$ apt-cache show xinetd
#...
Provides: inet-superserver
Conflicts: inet-superserver
$ apt-cache show inetutils-inetd
#...
Provides: inet-superserver, netkit-inetd
Conflicts: inet-superserver, netkit-inetd

Both provide and conflict with inet-superserver.

David the H. · 08-13-2010, 03:08 PM

Also, packages can occasionally have their names changed, be split into multiple separate packages, or separate packages can be merged into one. So apt sometimes needs to remove the package(s) with the old name(s) before it can install the new ones. This happens a lot with libraries with version numbers, for example, where libxyz23 gets updated to libxyz24.

So sometimes it takes a bit of deduction or research to determine exactly what's going on. One option is to use something like apt-file to list and compare the actual files that both the old package and new package install.

since1992trying · 08-14-2010, 04:09 AM

Dear AlucardZero, thanks for your help. Package tools remove other package if new packages can replace them.

Dear David the H., thanks for your help. Packages tools remove old package when the name of upgrading packages is changed.

Isn't there any well written documents regarding how this process works?

craigevil · 08-14-2010, 05:54 AM

Quote:

Originally Posted by since1992trying

Dear AlucardZero, thanks for your help. Package tools remove other package if new packages can replace them.

Dear David the H., thanks for your help. Packages tools remove old package when the name of upgrading packages is changed.

Isn't there any well written documents regarding how this process works?

take a look at
Grokking Debian GNU/Linux :
http://www.linuxquestions.org/questi...nu-linux-3073/

MTK358 · 08-14-2010, 04:11 PM

And sometimes two packages simply cannot coexist on the same machine, even if they don't replace each other. In that case, the package manager will ask you to either to abort installation or remove the conflicting package.

mcl123147 · 08-16-2010, 09:04 PM

Also, packages can occasionally have their names changed, be split into multiple separate packages, or separate packages can be merged into one. So apt sometimes needs to remove the package(s)