32.2.5. Explaining the Process
32.2.5. Explaining the Process The following steps illustrate what happens if the command useradd juan is issued on a system that has shadow passwords enabled: 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 greater than 499 is created. (Under Red Hat Enterprise Linux, UIDs and GIDs below 500 are reserved for system use.) A GID greater than 499 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 . 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. 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 32.1.1, "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 . 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. 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. 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 assign a password to the account using the passwd command and, optionally, set password aging guidelines.