On 8/2/05, Erik de Castro Lopo <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: > > > I'm not sure whether the upgrade will cause problems with existing packages. > > Does apt-get ensure that upgrades do not break existing packages or > > dependencies? > > > If a dependancy would break a package then apt-get would put it in > the list of packages it is removing and then give you the [Y/n] > option of continuing. > > This works at least 99% of the time. Very ocassionally a package > get through which doesn't list its dependancies correctly and > then can break if that unlisted dependancy is upgraded or removed. >
What Erik said :) The most common problems I've seen with Debian are that * Sometimes a package doesn't include everything you might expect - eg, I think it's possibly to install postgres clients without installing a postgres server. On reflection, this makes sense - you could well be wanting to access a postgres server on another machine, you don't actually need the libraries * Sometimes you'll install a package but it won't do anything useful until you do a bit of twiddling; eg, again using postgres, by default it's quite locked down and you have to do a few things to install it (from memory, it's configured to be completely inaccessible to everyone and you have to manually allow even access from localhost). Again, though, this makes sense - Debian favours "sensible defaults" - ie, defaults which are not going to break things. The only times I've ever seen dependency problems where my own fault - if you're going to live on Unstable and apt-get dist-upgrade without checking what you're doing first, you can expect things to break every now and then.. My biggest hint for doing upgrades or installs if you find that things aren't working as you expect: check /usr/share/doc/packagename/README.Debian (sometimes it's gzipped). This file will explain any differences between the upstream package and the Debian package (eg: postgres stores some files in different locations, has a different default pg_hba file), and will often give some basic use instructions as well. If you want to know more about Debian's packaging system, a good place to start would be the FAQ: http://www.us.debian.org/doc/manuals/debian-faq/ch-pkg_basics.en.html One of Debian's strengths is that the maintainers are very strict about maintaining their policies on packages, and ensuring that certain standards are met before the packages can be placed into the main repository (at least, the stable repository - unstable is called unstable for a reason :) You can read more about the policy, and what packages must do to comply, at http://www.us.debian.org/doc/debian-policy/ch-binary.html#s3.5 Debian also adheres (mostly?) to the Filesystem Hierarchy Standard (http://www.us.debian.org/doc/packaging-manuals/fhs/), which I quite like.. prevents some of the bizarre things I've seen on redhat - eg, all config files are on /etc, rather than redhat which arbitrarily stores BIND configs in /var/named. I'm sure that makes sense to someone, but I'm not that someone.. -- There is nothing more worthy of contempt than a man who quote himself in his email footer - Zhasper, 2005 -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
