LPI 702-100 Linux Professional Institute BSD Specialist Exam Practice Test

Permissions involve read, write, and execute roles that can be assigned to the owner, a group, or other users1.To use the chmod command, you must specify the permission you want to set and the file or directory you want to modify1.For example,chmod +rwx filenameto add permissions,chmod -rwx directorynameto remove permissions, orchmod +x filenameto allow executable permissions2.

There are two ways to specify the permissions with the chmod command: symbolic notation and numeric notation1.Symbolic notation uses letters and symbols to represent the user classes and the permissions1.Numeric notation uses octal numbers (0-7) to represent the permissions for each user class1.Each octal digit corresponds to a combination of read ®, write (w), and execute (x) permissions, as shown in the table below3:

Octal digit

Binary representation

Permissions

0

000

—

1

001

–x

2

010

-w-

3

011

-wx

4

100

r–

5

101

r-x

6

110

rw-

7

111

rwx

To use numeric notation, you need to provide three octal digits, one for each user class (owner, group, and others)1.For example,chmod 644 filenamemeans that the owner has read and write permissions (6), the group has read permissions (4), and others have read permissions (4)1.

In this question, the desired permission for the file text.txt is 750, which means that the owner has read, write, and execute permissions (7), the group has read and execute permissions (5), and others have no permissions (0)1. Therefore, the correct chmod command to change the permission of the file text.txt to 750 ischmod text.txt 750.

References:1: Chmod Command in Linux (File Permissions) | Linuxize2: How to change directory permissions in Linux | Pluralsight3: How to Use the chmod Command on Linux - How-To Geek

The swapctl command is used to list, add, or delete swap devices on BSD systems. It can also display the total amount of swap space available and used. The swapctl command takes various options to perform different actions, such as -l to list the swap devices, -a to add a swap device, -d to delete a swap device, and -s to show the swapsummary. The other options are not valid BSD commands for managing swap devices. References:

• swapctl(8) - OpenBSD manual pages
• FreeBSD Handbook - Chapter 19. The FreeBSD Booting Process
• FreeBSD Handbook - Chapter 9. Configuring the FreeBSD Kernel

The /etc/nsswitch.conf file defines the order of the name resolution methods used on a NetBSD system. It specifies the sources and their priority for various databases, such as hosts, services, protocols, etc. The sources can be files, DNS, NIS, or other services. For example, the following line in /etc/nsswitch.conf indicates that the hosts database should be looked up first in the /etc/hosts file, then in the DNS server, and finally in the NIS server:

hosts: files dns nis

References:

• nsswitch.conf(5) - NetBSD Manual Pages
• Chapter 23. The NetBSD Network Configuration Files

The nice command is used to run a command with a modified scheduling priority, which affects how much CPU time the command receives. The priority can be specified by the -n option, which takes an integer value between -20 and 19, where lower values indicate higher priority. By default, the nice value is incremented by 10, which means the command runs with lower priority than normal. Only the superuser can specify a negative increment, which means the command runs with higher priority than normal. For example, the command nice -n 5 date runs the date command with a priority of 5, while the command nice -n -10 ls runs the ls command with a priority of -10, but only if the user is the superuser. The nice command is useful for running CPU-intensive commands that do not need to finish quickly, or for running commands that need more CPU time than normal. References:

• nice - FreeBSD, the manual page for the nice command on FreeBSD.
• HowTo: Use ps, kill, nice, and killall To Manage processes in FreeBSD and OS X Unix Operating System - nixCraft, a tutorial on how to use the nice command and other process management commands on FreeBSD and OS X.

To update FreeBSD, the freebsd-update fetch command is used to download available binary updates, and the freebsd-update install command is used to apply the downloaded updates to the system. These commands are part of the freebsd-update utility, which supports binary security and errata updates to the FreeBSD base system without the need for manual compilation and installation2.

References:

• FreeBSD Handbook - freebsd-update

The sysctl command is used to set and get kernel state variables, including the FreeBSD security level. The security level is a variable named kern.securelevel, which can have values from -1 to 3, with higher values indicating more restrictions. The security level can only be increased, not decreased, unless the system is rebooted or in single-user mode. The security level affects various operations, such as loading kernel modules, changing immutable flags on files, and modifying device nodes12 References: 1: https://docs.freebsd.org/en/books/handbook/security/#security-basics-securelevels  2: https://www.freebsd.org/cgi/man.cgi?query=sysctl &sektion=8

The command mkdir (short for make directory) creates a new directory with the specified name. The command takes one or more arguments, which are the names of the directories to be created. If the name contains spaces or other special characters, it should be enclosed in quotes. For example, mkdir “My Documents” creates a directory named My Documents. The command also accepts some options, such as -p, which creates the parent directories if they do not exist, or -m, which sets the permissions of the new directory. For example, mkdir -p -m 755 /usr/local/bin creates the directory /usr/local/bin and its parent directories /usr and /usr/local, and sets the permissions of /usr/local/bin to 755 (read, write and execute for the owner, read and execute for the group and others). References:

• [mkdir(1) - FreeBSD Manual Pages]
• [How to Create a Directory in Linux - Linuxize]

The command that generates the output showing kernel module IDs, reference counts, addresses, sizes, and names iskldstatin FreeBSD. This command is used to display thestatus of loaded kernel modules, including those loaded dynamically. The output format shown in the question is characteristic ofkldstat, where it lists the kernel modules currently loaded into the system's memory along with their respective details.

References:

• FreeBSD Handbook or Manual Pages (man pages), specifically the section on kernel modules and thekldstatcommand.
• Linux Professional Institute BSD Specialist resources, which cover FreeBSD commands and utilities, including those for managing kernel modules.

The groups command is used to show the current user’s group memberships on BSD systems. The command prints the names of the primary and secondary groups that the user belongs to, separated by spaces. The primary group is the one that is assigned to new files and directories created by the user. The secondary groups are the ones that grant additional permissions or access to the user. For example, the output of groups for a user named alice might look like this:

alice wheel staff

This means that alice’s primary group is alice, and her secondary groups are wheel and staff. The wheel group is typically used for granting administrative privileges, such as using the su or sudo commands. The staff group might be used for granting access to certain resources or directories that are shared by a group of users.

The other options are either invalid commands or do not show the user’s group memberships. For example, group is not a valid command, ident is used to query an ident protocol server, showuser is not a valid command, and who is used to show who is logged on the system.

References:

• groups - FreeBSD groups(1) Manual Page1
• Group Management - FreeBSD Handbook2

The command route add default 192.168.1.1 is used to set the default gateway on a BSD system. This command adds a default route to the routing table, directing traffic to the specified gateway IP address when no other route matches.

References:

• FreeBSD Handbook - Routing
• OpenBSD Change, Add or Display Default Gateway

The pw utility is a command-line utility for the FreeBSD system user and group files, allowing the superuser an easy way of adding, modifying and removing users and groups. To lock a user account on a FreeBSD system, the pw lock command can be used with the username as an argument. This will prevent the user from logging in orchanging their password. To unlock a user account, the pw unlock command can be used with the username as an argument. This will restore the user’s access to the system. References:

• FreeBSD locking an account - nixCraft
• FreeBSD: How To Add, Delete Or Modify Users
• How to: FreeBSD User Administration - Atlantic.Net

The mailer.conf file is used to configure the mailer programs on a BSD system. It allows the system administrator to replace the default mailer programs, such as sendmail, with alternative ones, such as postfix or exim. The mailer.conf file contains a series of entries, each consisting of a label, an equal sign, and a command. The label is the name of the default mailer program, and the command is the path to the alternative mailer program that will be executed instead. For example, to replace sendmail with postfix, the mailer.conf file should contain the following entries:

sendmail /usr/local/sbin/sendmail send-mail /usr/local/sbin/sendmail mailq /usr/local/sbin/sendmail newaliases /usr/local/sbin/sendmail hoststat /usr/local/sbin/sendmail purgestat /usr/local/sbin/sendmail

The mailer.conf file is read by the mailwrapper program, which is a binary that acts as a wrapper for the mailer programs. The mailwrapper program is installed as /usr/sbin/sendmail and /usr/libexec/sendmail/sendmail, and it invokes the appropriate mailer program based on the mailer.conf file. Therefore, to replace the system MTA with another mail server program, the mailer.conf file needs to be updated with the path to the new MTA. References:

• Chapter 31. Electronic Mail | FreeBSD Documentation Portal
• DragonFlyBSD: mta

The command netcat is a versatile networking utility that can be used to read from and write to network connections using TCP or UDP protocols. It is often used for debugging and investigating the network and can be used to connect to a remote TCP service.

References:

• BSD Specialist Exam 702 Objectives - Linux Professional Institute
• FreeBSD Handbook - Networking

The zpool create command is used to initialize ZFS on one or more block devices and create a storage pool. A storage pool is a collection of devices that provide physical storage and data replication for ZFS datasets. The zpool create command takes the name of the pool and the devices to be added as arguments. For example, zpool create mypool c0t0d0 c0t1d0 c0t2d0 would create a pool named mypool with three devices. The other options are either invalid or do not initialize ZFS. References: 1: https://www.comptia.org/training/books/a-core-1-220-1101-study-guide, page 302  2: https://docs.oracle.com/cd/E19253-01/819-5461/gbchx/index.html, section “Creating a ZFS Storage Pool”

The file /etc/rc.conf contains values for Management Information Bases (MIBs) which are set during system startup. This file is used to configure system-wide settings, including the enabling and disabling of services, network settings, and other startup configurations2.

References:

• FreeBSD Handbook - The FreeBSD Booting Process

The file that defines the IP address of the default gateway on a FreeBSD system is /etc/rc.conf. This file contains various system configuration options, including network settings. To set the default gateway, the defaultrouter variable is used, followed by the IP address of the gateway. For example, defaultrouter=“192.168.1.254”. This setting will be persistent across reboots.

References

• FreeBSD Set a Default Route / Gateway - nixCraft
• Chapter 34. Advanced Networking | FreeBSD Documentation Portal
• Static default gateway on FreeBSD 8.0 - Super User

The inetd.conf file is the configuration file that needs to be edited before the TFTP service will start on a BSD system. The inetd daemon handles the TFTP service and other network services, and its configuration file contains settings that determine howthese services are managed. To enable the TFTP service, the corresponding entry in inetd.conf must be uncommented and properly configured. References:

• FreeBSD Handbook - inetd
• Linux Professional Institute BSD Specialist Exam Objectives

According to the BSD disklabel documentation1, the device name for a BSD disk slice consists of three parts: the disk name, the partition letter, and the slice number. The disk name is determined by the driver and the order of detection, and it usually follows the pattern of sdX, where X is a letter from a to z. The partition letter is a lowercase letter from a to p, excluding c, which is reserved for the whole disk. The slice number is a decimal number from 0 to 15, indicating the MBR partition that contains the BSD disklabel. Therefore, the device name for the first BSD disk slice in the disk label on the first partition on the second SATA disk on OpenBSD is /dev/sdlp2d, where sdl is the disk name, p is the partition letter, and 2 is the slice number.

References1: BSD disklabel - Wikipedia