2nd attempt since I seem to be having typing problems today...

I know this isn't the SL devos fault, but maybe I'm doing something 
unexpected or being silly.  Either seems fairly likely today.

It seems that yum shell doesn't understand check-update, so feeding it 
info like:

makecache
repo enable sl-damtpbits
repo enable .....
repo enable .....
makecache
check-update

results in:

$ yum shell yum.repo.shell
Loading "skip-broken" plugin
Loading "fastestmirror" plugin
Loading "priorities" plugin
Loading "kernel-module" plugin
Loading "changelog" plugin
Loading "downloadonly" plugin
Loading "tsflags" plugin
Setting up Yum Shell
Setting up repositories
sl-testedbits             100% |=========================| 1.1 kB    00:00
sl-mirror-base            100% |=========================| 1.1 kB    00:00
Loading mirror speeds from cached hostfile
Setting up repositories
sl-damtpbits              100% |=========================|  951 B    00:00
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
0 packages excluded due to repository priority protections
Setting up repositories
sl-mirror-security        100% |=========================|  951 B    00:00
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
0 packages excluded due to repository priority protections
Setting up repositories
sl-mirror-fastbugs        100% |=========================|  951 B    00:00
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
0 packages excluded due to repository priority protections
usage: yum [options] < grouplist, localinstall, groupinfo, localupdate, 
resolvedep, erase, deplist, groupremove, makecache, upgrade, provides, shell, 
install, whatprovides, groupinstall, update, groupupdate, info, search, 
check-update, list, remove, clean, grouperase >

None

      Shell specific arguments:
        config - set config options
        repository (or repo) - enable/disable repositories
        transaction (or ts) - list, reset or run the transaction set
        run - run the transaction set
        exit or quit - exit the shell

Leaving Shell

replacing 'check-update' with 'list updates' does something sane, and ends with 
a list of updates from the repos we now have enabled.

Just to make me feel less confident in yum the following does not do what I 
would expect:

repo list
repo enable sl-damtpbits
repo list

Instead of showing the repo being (temporarily) enabled it appears not to have 
affected the list at all.

$ yum shell
Loading "skip-broken" plugin
Loading "fastestmirror" plugin
Loading "priorities" plugin
Loading "kernel-module" plugin
Loading "changelog" plugin
Loading "downloadonly" plugin
Loading "tsflags" plugin
Setting up Yum Shell
>  repo list
repo id              repo name                                 status
...
sl-damtpbits         DAMTP extra bits for SL5                  disabled
...
>  repo enable sl-damtpbits
Setting up repositories
Loading mirror speeds from cached hostfile
Disabling Repository
>  repo list
repo id              repo name                                 status
...
sl-damtpbits         DAMTP extra bits for SL5                  disabled
...

however if I do makecache *before* doing repo enable then it works...

$ yum shell
Loading "skip-broken" plugin
Loading "fastestmirror" plugin
Loading "priorities" plugin
Loading "kernel-module" plugin
Loading "changelog" plugin
Loading "downloadonly" plugin
Loading "tsflags" plugin
Setting up Yum Shell
>  repo list
repo id              repo name                                 status
...
sl-damtpbits         DAMTP extra bits for SL5                  disabled
...
>  makecache
Setting up repositories
sl-testedbits             100% |=========================| 1.1 kB    00:00
sl-mirror-base            100% |=========================| 1.1 kB    00:00
Loading mirror speeds from cached hostfile
>  repo enable sl-damtpbits
Setting up repositories
sl-damtpbits              100% |=========================|  951 B    00:00
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
0 packages excluded due to repository priority protections
>  repo list
repo id              repo name                                 status
...
sl-damtpbits         DAMTP extra bits for SL5                  enabled
...

Finally (I hope) 'repo enable *' causes a python error and backtrace but then I 
think that is because it doesn't like wildcards here.

Is 'yum shell' something I shouldn't be playing with?  I was doing this to 
avoid having to make 2 calls to yum:

    yum --enablerepo=... --enablerepo=... makecache
    yum --enablerepo=... --enablerepo=... check-update

the makecache being to ensure that the cache (of the repos I'm normally leaving 
off) is fresh for the check-update.  From the manual I'd assumed it tuned into 
calling yum shell with something like:

repo enable ...
repo enable ...
makecache
check-update

Instead it seems I need to feed it:

makecache
repo enable ...
repo enable ...
makecache
list updates

which is fair enough if only I understood why...

BTW is the installonlyn yum plugin available (as part of some package 
somewhere)?

   http://people.redhat.com/~katzj/installonlyn.py

   #  A plugin for yum which only leaves n 'kernel' packages installed instead
   #  of infinitely doing installonly

I found a thread on a Centos mailing list suggesting it was part of yum-utils 
but that was for Centos-4 anyway.

   http://lists.centos.org/pipermail/centos-devel/2006-August/002361.html

FC 5 and 6 appear to have this functionality included in the base yum package 
and so does the yum in TUV-el5 if you see what I mean.

$ rpm -qlp yum-3.0.1-5.el5.src.rpm | grep installonlyn
installonlyn.py

I don't know if it is *enabled* by default in those releases though!

-- 
Jon Peatfield,  Computer Officer,  DAMTP,  University of Cambridge
Mail:  [log in to unmask]     Web:  http://www.damtp.cam.ac.uk/