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

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 2

You can use usermod, which will disable the password using an ! rather than an *.

usermod -L <username>

From the man page on usermod:

-L, --lock Lock a user's password. This puts a '!' in front of the encrypted password, effectively disabling the password.

Answer 3

Using dscl would give

dscl . -passwd /Users/myuser ""

Answer 4

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 5

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 6

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

Answer 7

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 8

On Linux I use:

sudo useradd -r -p \* -s /sbin/nologin -c "Comment My Daemon,,,"  -d "/var/uuu"  myuser

The next alternative must be more cross platform (if -r option is not available):

sudo useradd -K UID_MIN=100 -K UID_MAX=499 -K GID_MIN=100 -K GID_MAX=499 -p \* -s /sbin/nologin -c "Comment My Daemon,,,"  -d "/var/uuu"  myuser

Here:

• password in /etc/shadow will be setted to *. Without -p \* it will be !

• shell will be /sbin/nologin (You can use /bin/false too, but I think the /bin may be mounted too late on some systems). So user can't login

• -d sets user's homedir

IMPORTANT NOTE

Here -r creates a system user:

This flag is used to create a system account. That is, a user with a UID lower than the value of UID_MIN defined in /etc/login.defs and whose password does not expire. Note that useradd will not create a home directory for such an user, regardless of the default setting in /etc/login.defs. You have to specify -m option if you want a home directory for a system account to be created. This is an option added by Red Hat.

Option -r may not be present on your system. So to create a system user, that is not shown on your login screen, I think, you can use -K option. Something like: -K UID_MIN=100 -K UID_MAX=499. You can try option like:

-K UID_MAX=$(cat /etc/login.defs | grep ^UID_MIN | awk '{print $2}')

to automatically determine you UID_MAX, but I've not tested on OS X. You'll need use SYS_UID_MAX for UID_MIN if it's uncommented in /etc/login.defs

The same is for GID_MAX and GID_MIN for the system group id. (See GID_MIN and if uncommented SYS_GID_MAX in /etc/login.defs to use as GID_MAX)