[PLUG] Debian "alien" and "equivs" (care and feeding)

Karl M. Hegbloom karlheg at pdxlinux.org
Fri Nov 22 06:49:56 UTC 2002


On Thu, 2002-11-21 at 17:31, Cooper Stevenson wrote:
> Tyler,
> 
> Alien:
>   
>   http://kitenet.net/programs/alien/

Yes, just "apt-get install alien", then "man alien".  Another tool in
this category that every Debian admin should know about is "equivs".

It does not always work right, since Red Hat packages are most often not
Debian Policy compliant.  They go through a lot less trouble making
certain that things are installed in FHS compliant locations, I am
told.  The libraries are not always named the same either, and
interpackage dependancies can differ, since Debian tends to split things
up more, or the packages names are just different.

You might want to just open the RPM with "mc" (midnight commander) and
copy what you need out, then hand install it.  You should at least use
"mc" to poke around inside the generated .deb to see that the locations
it will install things are kosher and compatible.  Be aware that if you
hand install stuff, it can get blown away on upgrade (of the X11
packages, in this case), so to prevent that, you might like to place the
affected packages on "hold" status.

If you use "aptitude" (or ye olde "dselect") for your package management
tasks, you can put a package on "hold" using the "=" key.  That will
prevent "aptitude" from automaticly marking that package (and any
dependancies) for upgrade.  For example, I use this to hold onto my
custom build of "iptables", which I needed to match some special patches
(POM) applied to my kernel.  I've also used it, on "drizzle", to ensure
that the EVMS user space tools are not upgraded past the version built
into the kernel there.

I've used "equivs" to declare library dependancies for an older copy of
"Maple" installed on a computer at PSU.  Without the "equivs" generated
pseudopackage, "apt" would have uninstalled the libraries that older
version of "Maple" was built against, since it would have seen them as
no longer in use by anything.





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