Creating an user without a password

Question

I'm trying to create user without password like this:

sudo adduser \
   --system \
   --shell /bin/bash \
   --gecos ‘User for managing of git version control’ \
   --group \
   --disabled-password \
   --home /home/git \
   git

It's created fine. But when I try to login under the git user I'm getting the password entering:

su git
Password:...

When I leave it empty I get an error:

su: Authentication failed

What's wrong?

Answer 1

You've created a user with a “disabled password”, meaning that there is no password that will let you log in as this used. This is different from creating a user that anyone can log in as without supplying a password, which is achieved by specifying an empty password and is very rarely useful.

In order to execute commands as such “system” users who don't log in normally, you need to hop via the root account:

su -c 'su git -c "git init"'

or

sudo -u git git init

If you want certain users to be able to run commands as the git user without letting them run commands as root, set up sudo (run visudo as root and add a line like %gitters ALL = (git) ALL).

Answer 2

The --disabled-password option will not set a password, meaning no password is legal, but login is still possible (for example with SSH RSA keys).

To create an user without a password, use passwd -d $username after the user is created to make the password empty. Note not all systems allow users with empty password to log in.

Answer 3

If you want to access the system under the git user you should use sudo:

sudo -s -u git

or

sudo su - git