useradd user with group with same uid and gid

I want to add a user named "nexus" with uid as 1234567 (example number) and gid 1234567.

I'm running the following command:

sudo useradd -r -U -u 1234567 -g 1234567 -m -c "nexus role account" -d /sonatype-work -s /bin/false nexus

But I get the error:

useradd: group '1234567' does not exist

And if I do:

sudo useradd -r -U -u 1234567 -m -c "nexus role account" -d /sonatype-work -s /bin/false nexus

Then when I check id -u nexus it shows the correct uid (1234567) but when I check id -g nexus the gid is set to 999.

If I do sudo adduser --uid 1234567 nexus then the user and group ids are set the same.

Can I do the same with useradd or do I have to use adduser to achieve my goal?

I've been following this tutorial btw:

http://www.tecmint.com/add-users-in-linux/

P.S.: If I have to use adduser then can I do it without any human interaction; i.e.: automate the user creation via script?

EDIT:

This is the outcome of sudo adduser --uid 1234567 nexus

Adding user `nexus' ...
Adding new group `nexus' (1234567) ...
Adding new user `nexus' (1234567) with group `nexus' ...
The home directory `/home/nexus' already exists.  Not copying from `/etc/skel'.
adduser: Warning: The home directory `/home/nexus' does not belong to the user you are currently creating.
Enter new UNIX password: 
Retype new UNIX password: 
No password supplied
Enter new UNIX password: 
Retype new UNIX password: 
No password supplied
Enter new UNIX password: 
Retype new UNIX password: 
No password supplied
passwd: Authentication token manipulation error
passwd: password unchanged
Try again? [y/N] n
Changing the user information for nexus
Enter the new value, or press ENTER for the default
    Full Name []: Nexus
    Room Number []: 
    Work Phone []: 
    Home Phone []: 
    Other []: 
Is the information correct? [Y/n] y

Solution 1:

Thanks to Tom Yan, I've ended up solving my issue by creating a group with the same name then added the user to that group. So I did the following:

sudo groupadd -r -g 1234567 nexus \
  && sudo useradd -r -u 1234567 -g 1234567 -m -c "nexus role account" -d /sonatype-work -s /bin/false nexus

Solution 2:

Frankly, I think it's a bug(feature). The documentation indicates that you can use the '-U' option to simultaneously create the user and group at the same time. Intuitively you would think that in such a case, it would take the value from the '-g' flag and create the group accordingly.

[root@centos4]# useradd -U -u 200 -g 200 -m -d /home/ansible -s /usr/bin/bash ansible
useradd: group '200' does not exist

The example above is similar to your useradd command. However, if I simply remove the '-g 200' argument it works immediately. Although unfortunately it seems that the gid is allocated with the standard method.

[root@centos4]# useradd -U -u 200 -m -d /home/ansible -s /usr/bin/bash ansible
[root@centos4]# egrep ansible /etc/passwd
ansible:x:200:1000::/home/ansible:/usr/bin/bash
[root@centos4]# egrep ansible /etc/group
ansible:x:1000:

The answer to your question is that if you want to add user and group at the same time you have to remove the -g option. It's not as elegant as both you and I hoped, but its better than nothing.

Hope that helps. Take Care.