o get a list of all users you type (as users are listed in
/etc/passwd)
getent passwd
To add a user newuser to the system you would type
sudo adduser newuser
to create a user that has all default settings applied.
Bonus: To add any user (for instance anyuser) to a group (for instance cdrom) type
sudo adduser anyuser cdrom
You delete a user (for instance obsolete) with
sudo deluser obsolete
If you want to delete his home directory/mails as well you type
sudo deluser --remove-home obsolete
And
sudo deluser --remove-all-files obsolete
will remove the user and all files owned by this user on the whole system.
