Re: safe to purge older versions of installed software?

[Jörg-Volker Peetz <jvpeetz@web.de>]

Robert P. J. Day wrote:
> On Sun, 23 Aug 2009, Jörg-Volker Peetz wrote:
> 
>> Robert P. J. Day wrote:
>>>   this should be an easy one:  on my current (etch) system, there are
>>> a number of packages that have more than one version installed.  for
>>> example (and from memory), there are at least three versions of gcc
>>> installed.  am i safe to remove/purge the older ones?
>>>
>>>   perhaps a better question is, what is the command to list the
>>> packages that depend on a certain package?  in fedora, i'm used to
>>> running:
>>>
>>>   $ rpm -q --whatrequires <package>
>>>
>> aptitude comes in handy here:
>>
>> aptitude search '~i~D^<package>$'
>>
>> Since aptitude uses regular expressions search <package> is enclosed
>> by ^ and $ to distinguish, e.g., between gcc-4.3 and gcc-4.3-doc.
> 
>   i'm not sure what that's supposed to show me.  let me give you an
> example from my running lenny system.  if i run:
> 
>   $ apt-cache rdepends acpid
> 
> i get a list that includes, among other things, two installed
> packages -- acpi-support and acpi-support-base -- and a bunch of other
> packages that *aren't* installed.
> 
>   what i want now is a way to list only the *installed* reverse deps
> of acpid.  if i run (as you suggest):
> 
>   $ aptitude search '~i~D^acpid$'
> 
> i get null output.  what do you *think* i should see?
> 
> rday
<snip>
On my systems the output of

  $ aptitude search '~i~D^acpid$'

is

i   acpi-support-base               - scripts for handling base ACPI events such

since I have not installed package acpi-support.
By the way, in order to get the list of all packages which are not marked auto
and are not dependencies or recommendations of other packages issue

  $ aptitude search '~i!~M!(~R~i|~Rrecommends:~i)'
-- 
Regards,
Jörg-Volker.