### Upgrading OpenSUSE Leap online ###
       
       
       I use SUSE on my computer since SuSE Linux 9.1 (yes, I'm that old). Since a
       couple of years, I perform online upgrades - they are much more convenient
       than the CD- or DVD-based upgrade process. Upgrading OpenSUSE used to require
       changing all the registered repositories so they point to the next version,
       allowing YaST (zypper) to fetch the new packages. It is only recently that I
       learned about a neat trick to avoid this hassle: instead of hard-coding the
       OpenSUSE version in the repository URL, use the $releasever variable!
       
       Specifically, in YaST / Online Repositories, instead of such repos:
       
         http://download.opensuse.org/distribution/leap/15.1/repo/oss/
         http://packman.inode.at/suse/openSUSE_Leap_15.1/
       
       Use these:
       
         http://download.opensuse.org/distribution/leap/$releasever/repo/oss/
         http://packman.inode.at/suse/openSUSE_Leap_$releasever/
       
       The day-to-day working of such repositories is the same, but when time for
       upgrade comes, there is no need any more to change all your repositories.
       The online upgrade becomes a simple, almost enjoyable 4-steps process:
       
       1. Make sure your distribution is up-to-date
       
       2. Refresh zypper using the n+1 version of your SUSE system:
          # zypper --releasever=15.2 ref
       
       3. Perform the distribution upgrade:
          # zypper --releasever=15.2 dup
       
       4. Reboot