How to get rid of an uninstalled program's now-unneeded/un-used dependencies

[Stephen R Laniel]

On Fri, Jul 15, 2005 at 11:19:13PM +0900, Jeff Co wrote:
> I marked evince, a pdf viewer, for installation (in synaptic). I was told it
> needed a file that went something like libXYZ.  Then I removed evince. I ran
> deporphan again, but the list of files was the same. What happened to the
> dependency synaptic told me that evince needed? How come it wasn't on the list
> of deborphan?

Do other programs need libXYZ? If any other program depends
on it, it won't be removed. If evince, on the other hand,
was the only program depending on libXYZ, then deborphan
should have tagged it for removal.

To see whether another program depends on libXYZ, do

apt-cache show libXYZ

and look for the 'Reverse Depends' line. (Which really ought
to read, for clarity, "The following packages depend on
libXYZ.") If there's nothing in that line except for evince,
then you're free to remove it.

deborphan is fairly conservative, I think. It may be
avoiding uninstalling various packages for reasons unknown
to me.

deborphan has a '-d' option that lists which packages depend
on a given package. Below are the results for
'deborphan -d firefox', which should list those packages
depending on the firefox package. But I'm not clear how the
logic works: the surfraw package is listed there, but it
doesn't depend on firefox. It depends on 'www-browser', and
maybe deborphan is being conservative by assuming that
firefox is the only available www-browser. In this case I
assume it's conservatism: you really don't want to be
removing packages if doing so could hose your system.

firefox
      xpdf-reader
      openoffice.org2
      openoffice.org2
      desktop-base
      surfraw
      acroread-plugin
      mozilla-thunderbird
      apt-listbugs
      doc-debian
      apt-listchanges
      epiphany-browser
      docbook-xsl
      abs-guide
      yelp
      apache-doc
      devscripts
      ubuntu-desktop
      apache2-common
      firefox-gnome-support
      xscreensaver
      apache-common
      ggi-doc
      libgecko-cil
      tetex-doc
      mozilla-mplayer
      urlview
      mozilla-venkman
      xsane
      flashplayer-mozilla

-- 
Stephen R. Laniel
steve at laniels.org
+(617) 308-5571
http://laniels.org/
PGP key: http://laniels.org/slaniel.key
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