Package dependencies Debian

Question

I have a problem when installing certain software for Debian Jessie. I use apt-get install.

Sometimes it works, but in most cases I get the message:

The following packages have unsolved dependencies ... dependent on ... but ... should be installed. Problems can't be corrected. You have defect packages.

I get crazy. I have no clue how to tackle these problems. I don't need a quick fix for a certain installation but a general method or tutorial how to solve this package problem when it occurs.

Possible dupe of http://unix.stackexchange.com/q/121180/4671. — Faheem Mitha, Sep 03 '15 at 11:01
Unresolved dependencies are often the result of mixing different repositories and releases. It might be useful to know the content of /etc/apt/sources.list — , Sep 03 '15 at 12:00
@cryptix: Did you try to do: `apt-get update && apt-get upgrade` ? — perror, Sep 03 '15 at 13:03
Does `apt-get clean && apt-get update && apt-get upgrade && apt-get clean && apt-get autoremove --purge && apt-get dist-upgrade && apt-get clean && apt-get autoremove --purge` complete successfully, or where does it stop, and with which error? — Alex Stragies, Sep 03 '15 at 14:34

score 1 · Answer 1 · answered Sep 03 '15 at 18:07

I find the interactive mode of aptitude helpful in these situations.

It's worth reading the manual, but in short:

Start aptitude with no arguments
Press e to enter the resolver
Look at the first solution it offers. Probably there's an action you really don't want (e.g. uninstall your favourite game) - press r to mark that action rejected. (It's a toggle, so you can undo accidental marks with the same keypress).
If there's a suggested action that you think really should happen, you can toggle forcing that with a. Use this sparingly, as it can over-constrain the resolver quite easily.
Press . to see the next solution, which will take into account your rejections and accepts. With luck, this will be acceptable to you; if not, then repeat from step 3.
Press g to preview and g again to perform the update. Or, leave Aptitude, and the next aptitude install will apply the update (useful if you download packages automatically during off-peak times).

Package dependencies Debian

1 Answers1