Red Hat Enterprise Linux 3: System Administration Guide
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# 35.6. Explaining the Process

The following steps illustrate what happens if the command `useradd juan` is issued on a system that has shadow passwords enabled:

1. A new line for `juan` is created in `/etc/passwd`. The line has the following characteristics:

   - It begins with the username `juan`.

   - There is an `x` for the password field indicating that the system is using shadow passwords.

   - A UID at or above 500 is created. (Under Red Hat Enterprise Linux, UIDs and GIDs below 500 are reserved for system use.)

   - A GID at or above 500 is created.

   - The optional GECOS information is left blank.

   - The home directory for `juan` is set to `/home/juan/`.

   - The default shell is set to `/bin/bash`.

2. A new line for `juan` is created in `/etc/shadow`. The line has the following characteristics:

   - It begins with the username `juan`.

   - Two exclamation points (`!!`) appear in the password field of the `/etc/shadow` file, which locks the account.

     | Note
     | If an encrypted password is passed using the `-p` flag, it is placed in the `/etc/shadow` file on the new line for the user.

   - The password is set to never expire.

3. A new line for a group named `juan` is created in `/etc/group`. A group with the same name as a user is called a user private group. For more information on user private groups, refer to Section 35.1 Adding a New User.

   The line created in `/etc/group` has the following characteristics:

   - It begins with the group name `juan`.

   - An `x` appears in the password field indicating that the system is using shadow group passwords.

   - The GID matches the one listed for user `juan` in `/etc/passwd`.

4. A new line for a group named `juan` is created in `/etc/gshadow`. The line has the following characteristics:

   - It begins with the group name `juan`.

   - An exclamation point (`!`) appears in the password field of the `/etc/gshadow` file, which locks the group.

   - All other fields are blank.

5. A directory for user `juan` is created in the `/home/` directory. This directory is owned by user `juan` and group `juan`. However, it has read, write, and execute privileges only for the user `juan`. All other permissions are denied.

6. The files within the `/etc/skel/` directory (which contain default user settings) are copied into the new `/home/juan/` directory.

At this point, a locked account called `juan` exists on the system. To activate it, the administrator must next assign a password to the account using the `passwd` command and, optionally, set password aging guidelines.

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