I am not yet a true "Linux guy" and I have the following doubts about how exactly do the following shell procedure (a list of commands steps) founded in a tutorial that I am following (I want deeply understand what I am doing before do it):

sudo passwd root

then login again as root

usermod -l miner pi
usermod -m -d /home/miner miner
groupmod -n miner pi
exit

So at the beginning it enable the root account and I have to login again in the system as root...this is perfectly clear for me.

And now I have the followings doubts:

1) The usermod command:

usermod -l miner pi
usermod -m -d /home/miner miner

Reading the official documentation of the usermod command I understand that this command modify the informations related to an existing account

Reading the documentation it seems to me that the -l parmether modify the name of the user pi in miner and then the -m -d paramether move the contents of the old home directory to the new one (named miner) and use this new directory as home directory

My doubt is: what exactly do the executions of these operation? I think that:

• Rename the existing pi user in miner

• Then move the content of the old home directory (the pi home directory? or what?) into a new directory (/home/miner) that now is the home directory for the miner user.

Is it right?

The the second doubt is related to this command

groupmod -n miner pi

It seems to me that change the group name from pi in miner

But what exactly is a group in Linux and why is it used?

Tnx