questions on package management

[Eddie G. O'Connor Jr.]

On 07/13/2013 07:42 PM, lee wrote:
> "Eddie G. O'Connor Jr." <eoconnor25 at gmail.com> writes:
>
>> On 07/13/2013 10:07 AM, lee wrote:
>>> "Eddie G. O'Connor Jr." <eoconnor25 at gmail.com> writes:
>>>
>>>> On 07/12/2013 09:11 PM, lee wrote:
>>>>> Another question: It is possible to have version 1 and version 2 of
>>>>> package A installed at the same time, like version 1 from Fedora 17 and
>>>>> version 2 from Fedora 18.  Imagine this package A provides a file
>>>>> '/bin/ls'.
>>>>>
>>>>> Which version of '/bin/ls' will be the one in use?  What about
>>>>> compatibility issues in such a case?
>>>>>
>>>>> (Please don't say it's not possible; I have had it happen.)
>>>>>
>>>>>
>>>> Hmm....well I'm not sure how I would go about fixing that.....maybe
>>>> just purge them all and get the latest versions from the repo?....
>>> What I did was removing the F17 packages.  Still I'm curious, it's
>>> surprising that it is possible to have two versions of the same package
>>> installed.
>>>
>>>
>> I believe it's because everything regarding Linux is a "file" of some
>> sort, and you can have multiple files on your machine with the same
>> name, maybe not EXACTLY the same...but "close enough".
> There can be only one '/bin/ls' (unless you replace the file while it's
> still open; in that case, the old one invisibly stays (or something like
> that) until it's closed).
>
> Think of emacs or a library, you can replace the file and it will
> continue to be used by whatever used it before you replaced it.  Start
> another instance of emacs or of a software that uses the library after
> replacing emacs or the library, and the new version will be used.
>
> That's why it's sometimes a good idea to reboot after upgrades.
>
>> (LibreOffice 4.0.0...and LibreOffice 4.0.1...not the same...but not
>> that different either!) I usually try to keep one instance of every
>> app in/on my machine, and the stuff that builds up over time that I
>> know isn't needed? I delete....(I especially like the "Bleach Bit" app
>> and "YumEX" for helping in that regard!!)
> You find that updating something like LO from 4.0.0 to 4.0.1 doesn't
> remove 4.0.0?  Isn't that exactly one of the things the package
> management should take care of?
>
> Imagine upgrading whatever package provides ls from 4.0.0 to 4.0.1 and
> having both installed at the same time.  There is still only *one*
> /bin/ls, not two of them.  Which one is it gona be?
>
>
True....I was mistaken;y just generalizing ....thanks for clearing that up!!


EGO II