let's suppose you want to install an old OpenNMS release.
In http://sourceforge.net/projects/opennms/files/OpenNMS/old/ you can find a lot of releases
Windows version: standalone-opennms-installer-1.12.3-1.zip
generic Linux: opennms-1.12.3.pkg.gz
unzipping opennms-1.12.3.pkg.gz will produce a file opennms-1.12.3.pkg that on CentOS appears as "pkg Datastream (SVR4)"
which is the safest way to install it ? I found a script pkg2rpm.pl on this page:
but it doesn't work well, even fixing the .spec generation it still has problems and I'm not able to obtain the rpm.
Probably this is not the right way, as pkg is generated it should also be extracted. Any ideas ?