Default shell not being selected with useradd

Question

I have a fresh version of Ubuntu 16.04.1 installed and have tried to create a new user account through root. I have changed the SHELL line in /etc/default/useradd to read as follows:

SHELL=/bin/bash

(it previously read /bin/sh)

Executing useradd -D provides the following output:

GROUP=100
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/bash
SKEL=/etc/skel
CREATE_MAIL_SPOOL=no

I then try to create a user as follows:

useradd -m -G sudo -c "David Buckley" david

Yet the default shell is still /bin/sh. More specifically, the /etc/passwd file reads as follows:

david:x:1000:1000:David Buckley:/home/david:

On a slightly, potentially related note, the new user does not receive sudo access. It is given the groups david sudo, and the /etc/sudoers file includes the lines (uncommented):

# Allow members of group sudo to execute any command
sudo    ALL=(ALL:ALL) ALL

What might I be doing wrong to cause this?

Answer 1

Oddly enough, this happened to me too yesterday on a server running Ubuntu 16.04 LTS.

I have no concrete answer as to why this happens, but here is a quick solution that worked for me:
Don't use useradd, use adduser instead!

DESCRIPTION

adduser and addgroup add users and groups to the system according to command line options and configuration information in /etc/adduser.conf. They are friendlier front ends to the low level tools like useradd, groupadd and usermod programs, by default choosing Debian policy conformant UID and GID values, creating a home directory with skeletal configuration, running a custom script, and other features.

As for sudo, you have to log out that user — and then log back in — for the new group settings to have an effect.

Here's a good link on useradd vs adduser.

Answer 2

This is a known bug in Ubuntu's useradd (added by a Ubuntu-specific patch). It ignores all the settings specified in /etc/defaults/useradd...

The workaround, as indicated in maulinglawns' answer, is to use adduser instead, which is the recommended tool for adding non-system users in Debian derivatives.