Just in search of command which can give clue so that I need not to go to Bios.
Yes, but, what do you need one for
If you installed it, then you already know.
If you are troubleshooting someone elses, then you should look at the bios anyway.
I ask because it sounds like you are trying to do something which has another method.
You have to try some sleuthing to discover the nature of installed raid (or install the vendors raid management tools ... but you need to knew it is raid before you can do that.)
is useful for discovering software raid too.
lists all discovered raid devices with formats and levels. HW raid won't count. If a fake raid was not set up via dmraid, then it may not show either - it may use some other software.
soft raid usually has device files with names like md0 and md1 - so
should discover them.
Fakeraid arrays do not have systematic names. If you are lucky the volumes will have "ARRAY" in their names.
will also provide clues - usually it fails to find a partition table on raid drives.
should list any special drivers for fake raid.
Basically, for fake raid, you should go into bios: it is so much easier.