An idea on extending the "Package users" approach

Angel Tsankov fn42551 at fmi.uni-sofia.bg
Thu Jan 8 23:00:11 PST 2009


> Angel Tsankov wrote:
>
>> Let's say I've installed two versions of the same software, e.g.
>> Python 2.6.1 and Python 3.0.  At some point in the future, I decide I
>>  no longer need Python 2.6.1 and want to remove it.  How easy would
>> it be to also remove the info about it from the .plan and .project
>> files?
>
> Totally trivial.
>
> The key here is that pinky (and finger) read the .project and .plan
> files for a user from that user's home directory.
>
> Try this:
>
> 1) call pinky on yourself:
> cd ~
> pinky -l ${USER}
>
> 2) edit the .project file in your own home directory
> echo "foo" >> .project
> echo "bar" >> .project
> echo "baz" >> .project
>
> 3) call pinky on yourself again:
> pinky -l ${USER}
>
> 4) edit the .plan file in your own home directory
> echo "No Plan ... let's wing it." >> .plan
> echo "line two" >> .plan
> echo "line three" >> .plan
>
> 5) call pinky on yourself again:
> pinky -l ${USER}
>
>
> You should see that the .plan and .project files are simple text files
> which you may edit with any text editor, there is nothing magic about
> them, except that finger and pinky go looking for those names in the
> users' home directories.
>
> I imagine this already gives you enough that your question is answered.
>
> However, just for completeness, let's imagine that you have one user
> "python" for Python 2.6.1 and another user "python3" for playing with
> Python v3.
>
> In this case, you'd have a /usr/src/python/.project file with whatever
> info you've elected to put into the .project file (say, the version and
> two patch file names), and you'd also have a /usr/src/python3/.project
> file with the separate Python v3 information there.
>
> When you decided that you were done with your Python v2, and that
> everything really does work finally with python3, you'd simply remove
> the python2 package, and it's home (/usr/src/python/) directory, in
> which case the /usr/src/python/.project file vanishes with it.
>
>
> Alternatively, you might have decided that you have one user for *every*
> version of python you have installed. By the way, this is not something
> I do, because I don't trust Version X and Version Y to not stomp on each
> others' files. Nor do I trust myself to keep it straight.
>
That's exactly the reason I was thinking that it might be a good idea to 
have a distinct user not only for each package but also for each version of 
any package; something like "version users".

> But supposing this is your situation, then you'd probably want to put
> more verbose information in the /usr/src/python/.project rather than the
> sparse approach of simply echoing the version information in there, you
> might wish to open up your favorite text editor and write a nice
> descriptive summary with whatever notes will be useful when you go to
> make changes in the future.
>
> Then, when later you come back to remove Python 2, you'll simply edit
> the .project file to reflect the new state of affairs.
>
First, thanks for the detailed explanation as well as for the examples --  
they were all really useful!

Now, what I meant is if it would be easy to do all the changes, let's say, 
from a bash script (so as to automate certain tasks; I didn't mention this 
in my first post -- sorry for this) if we use only one user for management 
of all Python packages (I'm reconsidering the "version-users" idea).

--Angel 




More information about the lfs-chat mailing list