Another computer can be as well virtual machine. I cannot make disk clone because of hardware differences and settings.
I have computer A, installed and running, I also have computer B. I will install the same OS on B, so I would get the same base system.
Then by hand I will add the same repositories as on A.
But the last stage is beyond me -- how to install the same packages as on A? Note, that the version has to match, not only package name.
Of course I am looking for automatic way, not installation manually one by one.
In effect I should get completely different hardware configuration, clean settings (no old passwords, etc), but identical software selection.
How to do it?
The packages (per version) are available but are not the latest ones. The point of this is to make a "copy" of running system, upgrade packages on computer B (copy), test if it works, if yes, then upgrade A. With every new OS version I am hit by many regression bugs, and I have to test it more methodically, than test-live & panic.