Is it the cfg code that takes care of the selection between the 3 programs or is it the lst-code?
Being an oldtimer (I dont dare tell you how old I am) having been engaged with data
processing since the days of punched cards, I have programmed in assembler,
cobol, main-frames, ms-dos etc.etc. But linux is way beyond me, this is
absolutly "greek" !
Ok, this is one example of one of the reasons why I "spend" (invest?) my time trying to answer and help. No matter how "old" you think you are, there is always something to learn, and each and every one of us has been a newbie in regards to "some new topic". When I read and learn by myself, and I find out that that's not enough, it's always very helpful to find someone that can give at least some kind of direction.
Now, to the point. UBCD uses by default a SysLinux boot menu. Since UBCD v5 , UBCD includes an alternative Grub4Dos boot menu. You can select the alternative menu from the last line listed in the boot menu (from SysLinux to Grub4Dos and viceversa). For most simple cases, the two menu systems are equivalent.
SysLinux takes its configuration from specific *.cfg files (like "custom.cfg").
Grub4Dos takes its configuration from specific *.lst files (like "custom.lst").
In theory, I could have give you "only" the custom.cfg file for edition, and it would have successfully worked. By editing also the custom.lst, you have both menu systems available for your UBCD customization.BTW, you previously asked if you made a mistake by changing the original custom.cfg/custom.lst (with "#" characters for commenting lines). Had you simply ADDED (to the end of those 2 "custom.*" files) the relevant and respective code I posted, it would had been enough and successful.
Fortunately, you "happened to mention" that you made those "extra" editions, and Icecube was able to help you.
In short: "cfg" and "lst" files are "equivalent" in their goal; one for SysLinux, one for Grub4Dos.
I can start it manually though, by typing : "stress --cpu etc etc etc". Should some linux-lines be altered so that selection 2 will start autmatically or is it ment for only manual start?
The "help text" of your boot menu says it clearly.
This menu item launches Stress with the "--help" parameter that displays all possible options. You need to run it again with the stress test options that you prefer.
Once you select this program, you simply are starting it with the "--help" command line parameter, so you can obtain the complete list of available command line parameters.
With that help screen, you can decide exactly which parameters you want to use to run the program in that specific session (specific situation/cpu/ram/time...).
specify those parameters (the ones displayed as result of the "--help" parameter) in the boot menu directly, instead of the "help" parameter, but then you would have less flexibility in different testing systems/situations.