How do you create a user with no password?

Question

In os X it's possible to have users without passwords. If you inspect them with dscl their password show up as *. This is used for system users such as users for databases like mysql, pgsql etc. What's nice about this is that these users doesn't show up at the login screen and you can't login as them without sudo etc.

After deleting such a user trying some things out I wanted to recreate it, but couldn't. I could manage to get a user with a blank password and I could set the password to *. But none had the same effect as above, as the user showed up on my login screen.

How do you create such a user?

Answer 1

A user in /etc/passwd with home directory of /dev/null and shell of /sbin/nologin, can be used for sudo ing commands, but can't actually be logged into, for example;

from my /etc/passwd

tcpdump:x:104:441:added by portage for tcpdump:/dev/null:/sbin/nologin

I half remember this will make it disappear from the XDM login screen too, but I don't use XDM anymore, so that's a guess :-)

Answer 2

If you are on Ubuntu you can swap in the password for the Ubuntu user in /etc/shadow check out this article:

http://www.psychocats.net/ubuntucat/creating-a-passwordless-account-in-ubuntu/

Answer 3

You can run passwd --delete <username> after creating the user with adduser. After this, you'll be able to login without entering a password.

Answer 4

I can't be certain about OSX, but on FreeBSD you can use:

pw add user mymuser -g mygroup -s /nonexistent -h -

the value of - passed to the -h option tells pw to set the password field in master.passwd to *, thus creating a no-login account. Setting the shell isn't strictly necessary, but avoids a shell check from /etc/pw.conf.

Answer 5

Leaving the password field empty for the user in the passwd file will work.