Legit 102-500 Exam Download

Running the command chsh -s /bin/false with the user name will change the user’s login shell to /bin/false, which is a program that does nothing and returns a non-zero exit code. This means that the user will not be able to execute any commands or start an interactive shell session. This is a common way to disable a user’s login without disabling the account completely, which can be useful for users who only need to access the system via scp, sftp, or other non-interactive services. However, this method does not prevent the user from authenticating with the system, and it may not work with some services that do not rely on the login shell, such as ssh with a forced command. Therefore, it is not a foolproof way to secure the system from unauthorized access. References: 1234

The groupdel command is used to delete a group from a Linux system. It removes the group name from the /etc/group and /etc/gshadow files, but not the group’s configuration files, entries, or account files. The groupdel command requires root or sudo privileges and does not accept any options except for one for chroot. The groupdel command does not print any output on success, but it will display an error message if the group does not exist or if it is the primary group of an existing user. The groupdel command is part of the shadow-utils package, which provides tools for managing user and group accounts. The groupdel command is also compatible with the Linux Standard Base (LSB) specification, which defines a common set of commands and utilities for Linux distributions. References: 1234

 The /etc/passwd file assigns a user to its primary group by specifying the group ID (GID) of the primary group in the fourth field of each line. The /etc/passwd file contains the basic information for each user account on a Linux system, such as the user name, user ID (UID), group ID (GID), home directory, login shell, etc. The format of each line is:

username:password:UID:GID:comment:home:shell

For example, the following line assigns the user bob to the primary group bob, which has the GID of 1001:

bob:x:1001:1001::/home/bob:/bin/sh

The /etc/passwd file can be viewed and modified by the root user or by using the useradd, usermod, or userdel commands123. The other files listed in the options do not assign a user to its primary group. The /etc/pgroup file does not exist by default on most Linux systems, and it is not related to the primary group. The /etc/shadow file contains the encrypted passwords and other information for each user account, but not the primary group4. The /etc/group file contains the information for each group on the system, such as the group name, group password, group ID, and group members, but not the primary group of each user5. The /etc/gshadow file contains the encrypted passwords for group accounts. References: 12345

The /etc/passwd file stores local accounts of the system. It is a readable text file and uses colons (:) to separate the fields. This file helps with converting user IDs to names (and back). It is fine that all users can read this file, but they should not be able to change fields. Therefore, the most correct permissions for /etc/passwd are -rw-r–r–, which means that only the owner (root) can write to the file, and everyone can read it. The /etc/shadow file contains information about the system’s users’ passwords. It is owned by user root and group shadow, and has 640 permissions. The password is stored as a long string of characters, which is a combination of the hashing algorithm, optional salt applied, and the hashed password itself. Other users are not allowed to read the file directly, to prevent them from gathering hashed passwords of others. Therefore, the most correct permissions for /etc/shadow are -r--------, which means that only the owner (root) can read the file, and no one else can read or write to it. References: