[CentOS] Old and new package version numbers during RPM update

Rex Dieter
Mon, 29 Jun 2015 19:29:23 -0000

Anand Buddhdev wrote:

> Hi CentOS folk,
>
> In an RPM post-install script, is it possible to know the previous
> version number, and the new version number of a package if it's an
update?
>
> I need to know this, because for a certain package, if updating from
> version 1.x to 2.x, I need to run a program to convert the config file
> of the package from version 1.x format to version 2.x format.
>
> I've looked at SPEC file documentation, but haven't found anything
> relevant.

triggers can support that, you can implement a trigger scriplet to run only
if upgrading from < 2.x, using something like:

%triggerun foo < 2.x
convert_config...

See also:
http://rpm.org/api/4.4.2.2/triggers.html


-- Rex