How to set a user without password on Linux ?

[yyghp]

Is that possible to set a user without password on Linux ?

I have a device which is a terminal,wants to login to the Linux automatically. That is, the users who use the device doesn't have to type in any user authentication info. before they can sign in to the Linux server.

( Security issue is not concerned at this moment, however, better solution will be appreciated )

Thanks a lot !

[Stuart Browne · Accepted solution]

Yes, there is a way.

Modify '/etc/shadow', and remove the encrypted password for the given user, i.e.

genericuser:$1$2PCgTfmF$BbNzJv.sc7iNJ2xB.iHfP.:12407:0:99999:7:::

to:

genericuser::12407:0:99999:7:::

If you ensure the matching /etc/passwd entry has an 'x' in the 2nd field (like all shadow-encrypted passwords), then the account will have 'no' password.

There is no nice neat command to remove a password in this manner. The 'passwd' command will force an unencryptable password (!!) if none is supplied.

WARNING: Manually modifying the passwd and shadow files is dangerous. Ensure you have a backup copy before doing anything, and make sure you can still log in (in another session) as user/root before logging the current session out.

[Alexander Chuzhoy]

if you don't use shadow passwords:
simply remove seconds column from the user in /etc/passwd.So the entry will look like the following.

user::500:500::/home/user:/bin/bash


use "authconfig" utility to set/unset shadow passwords.

[Gopi Sekar]

I believe you dont have to touch /etc/shadow file, just edit /etc/passwd file and remove 'x' in the user id entry.

ex:

user1:x:19910:19901:/home/user1:/bin/bash

change to

user1::19910:19901:/home/user1:/bin/bash

Hope this helps,
Gopi

[Paul Cross_1]

Since you are asking for a better (more secure) solution, I would recommend using ssh with authorized_keys. The user wouldn't have to login with a password, but would HAVE a password, and all trafic would be encrypted as well. OR (less secure) you could use .rhosts for logins. While more secure than having no password, it is defininitely a distant second choice over ssh.

-paul.