Linux – How to set the password of a new user after the account has already been created

You can use chpasswd

The chpasswd command administers users' passwords. The root user can supply or change users' passwords specified through standard input. Each line of input must be of the following format.

username:password Only root users can set passwords with this command.

Example 1:

echo username:password | chpasswd 

Example 2:

Also for security you can pass encrypted password to chpasswd

# Create Password in Encrpyted Form Using below command
# perl -e'print crypt("YourPassword", "salt")' ; echo -e

echo username:cryptedPass | chpasswd -e

By default on enterprise GNU/Linux and its derivatives, the adduser command creates a user which is disabled until you explicitly specify a password for that user.

Here is an example on CentOS 6.5, which should be the same as Scientific Linux.

 $ sudo adduser test
 $ sudo grep test /etc/shadow
 test:!!:123456:0:99999:7:::

that's because in the /etc/shadow file, the password field is !!, as you can see in the example.

Once you run passwd for this account, it will change the user's password and allow the user to be able to login.

So what you should be able to do is the following to have a user without a password, simply create an account then delete the password.

 $ sudo adduser test
 $ sudo passwd -d test
 Removing password for user test.
 passwd: Success
 $ su test
 $ whoami
 test

now any user should be able to use su and login as the user test in my example. You will not have to use sudo to login as the account.

Although this is possible and you can have an account without a password, it is not advised. If you simply set the password for the user, you should be allowed to login.

$ sudo passwd test
[sudo] password for <YOURACCOUNT>:
Changing password for user test.
New password:
Retype new password:
passwd: all authentication tokens updated successfully.