When I use the adduser command on fedora, it's not aksing for password or fullname. It's working exactly like useradd.
I don't understand why.
[hugues@localhost ~]$ sudo adduser user1 [hugues@localhost ~]$ sudo useradd user2 And it creates two users in /etc/passwd
user1:x:1004:1010::/home/user1:/bin/bash user2:x:1005:1011::/home/user2:/bin/bash in fedora there is only useradd command, adduser is just a symlink to useradd.
you can check that with the following command:
ls -ld /usr/sbin/adduser the output of the command:
[root@fedora28 ~]# ls -ld /usr/sbin/adduser lrwxrwxrwx. 1 root root 7 Feb 6 05:37 /usr/sbin/adduser -> useradd 
ls -ld /usr/sbin/adduser and ls -ld /usr/sbin/useradd display files with different sizes, so I'm curious about the output on Fedora) adduser is a symlink to useradd. adduser command, and looked in the package changelog, which includes: Mon Oct 27 1997: - obsolete adduser. I guess I'm getting old. :) ls -ld to the answer useradd is the only command of them two which is available on all Unix style systems (I know of).
On Debian and its derivatives, adduser is a wrapper to useradd which adds some comfort like generating a same named group by default.
In Fedora, they are the same.
useradd is not a POSIX utility, neither is adduser.