CentOS - Mar 2008 - alternatives package?

Hi,

In my struggle today to get python2.4 installed on my CentOS4 system, I saw 
that it installed a packaged called alternatives which is supposed to handle 
symbolic links to default commands in a nice clean, structured way. 
However, I am having trouble understanding how this thing works.

I have read the man page half a dozen times already, and yet the alternative 
link for python which was installed doesn't seem to follow what is written 
in the man page.  I am trying to modify the default behaviour for it, but 
having a lot of difficulty.

Of course, with a name like "alternatives", it makes searching Google,
tldp.com, etc very difficult.

Does anyone have experience with this package and/or can anyone point me in 
the direction of some good examples, documentation for it?  Something a bit 
more explanative than the man page.

Thanks!

Eric

On Tue, 2008-03-11 at 18:20 -0400, Eric B. wrote:
> In my struggle today to get python2.4 installed on my CentOS4 system, I saw
> that it installed a packaged called alternatives which is supposed to
handle
> symbolic links to default commands in a nice clean, structured way. 
> However, I am having trouble understanding how this thing works.
> 
> I have read the man page half a dozen times already, and yet the
alternative
> link for python which was installed doesn't seem to follow what is
written
> in the man page.  I am trying to modify the default behaviour for it, but 
> having a lot of difficulty.
As an end-user, the only important commands you need are:

"alternatives --display <name>": Show information about an
alternative
"alternatives --config <name>": Allow selection of an
alternative
"ls /var/lib/alternatives": Show valid alternatives

-- 
Ignacio Vazquez-Abrams <ivazqueznet at gmail.com>

PLEASE don't CC me; I'm already subscribed
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> On Tue, 2008-03-11 at 18:20 -0400, Eric B. wrote:
> > In my struggle today to get python2.4 installed on my CentOS4 system,
I
> > saw
> > that it installed a packaged called alternatives which is supposed to 
> > handle
> > symbolic links to default commands in a nice clean, structured way.
> > However, I am having trouble understanding how this thing works.
> >
> > I have read the man page half a dozen times already, and yet the 
> > alternative
> > link for python which was installed doesn't seem to follow what is
> > written
> > in the man page.  I am trying to modify the default behaviour for it, 
> > but
> > having a lot of difficulty.
>
> As an end-user, the only important commands you need are:
>
> "alternatives --display <name>": Show information about an
alternative
> "alternatives --config <name>": Allow selection of an
alternative
> "ls /var/lib/alternatives": Show valid alternatives
That's what I thought too, however, if I look in my /usr/bin directory I see
the following:
# ls -l /usr/bin/pyt*
lrwxrwxrwx  1 root root   18 Mar 11 17:43 /usr/bin/python -> 
/etc/alternatives/links/|usr|bin|python
lrwxrwxrwx  1 root root   40 Mar 11 17:31 /usr/bin/python2 -> 
/etc/alternatives/links/|usr|bin|python2
-rwxr-xr-x  2 root root 5396 Dec 11 05:30 /usr/bin/python2.3
-rwxr-xr-x  1 root root 3268 Sep 28  2005 /usr/bin/python2.4

but
# alternatives --display python

returns nothing.  If I look in /var/lib/alternatives, I only find
"print",
"mta" and "etags".

So I'm not quite sure how to update / modify the python alternative to point
to another location instead.  If I look in /etc/alternatives/links I see the 
following:
# ls -l /etc/alternatives/links/
total 12
lrwxrwxrwx  1 root root 18 Mar 11 17:31 |usr|bin|python -> 
/usr/bin/python2.4
lrwxrwxrwx  1 root root 15 Mar 11 17:31 |usr|bin|python2 -> /usr/bin/python
lrwxrwxrwx  1 root root 34 Mar 11 17:31 |usr|share|man|man1|python.1.gz -> 
/usr/share/man/man1/python2.4.1.gz


The rpm installer automatically created these links when I yum installed 
python24 from pyvault.  (It automatically installed the alternatives pkg).

Thanks for the help!

Eric