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

The command chown changes the ownership of a file or directory. The syntax is chown user:group file, where user is the new owner and group is the new group of the file. In this case, the superuser can grant the user bob write permission to the file by changing both the owner and the group of the file to bob. This way, bob will have the same permissions as the original owner, which is read and write. Alternatively, the superuser can also use the command chmod to change the permissions of the file without changing the ownership. For example, chmod g+w bobsfile will add write permission to the group, and chmod o+w bobsfile will add write permission to others. However, these commands will also affect other users who belong to the same group or are not the owner or the group of the file. References:

• FreeBSD Handbook: File and Directory Ownership
• FreeBSD Handbook: File and Directory Permissions
• Linux Professional Institute BSD Specialist: 702.1 Filesystem and Devices

A /24 IPv4 prefix provides 256 IP addresses, which is the number of addresses in one octet (2^8). A /28 subnet has 16 IP addresses (2^4). To calculate how many /28 subnets can fit into a /24 prefix, divide the total number of addresses in the /24 prefix by the number of addresses in a /28 subnet: 256 / 16 = 16. However, since each subnet has network and broadcast addresses that cannot be used for hosts, the actual number of usable subnets is less. In practice, you can create 16 subnets, each with 14 usable IP addresses for hosts.

References:

• Subnet Cheat Sheet
• IP Subnet Calculator

A symbolic link, or symlink, is a special type of file that points to another file or directory on the file system1. When creating a symbolic link with the ln command, the syntax is as follows:

ln -s target link

where target is the file or directory to link to, and link is the name of the symbolic link2. If the link name already exists, the ln command will fail and display an error message indicating that the target already exists3. This is because the ln command does not overwrite existing files or directories by default4. Therefore, the only way to create a symbolic link with the same name as an existing file or directory is to manually remove the existing target first, and then run the ln command again. Alternatively, the ln command can be used with the -f (force) option, which will remove the existing target and create the symbolic link in one step4. However, this option is not mentioned in the question, so the correct answer is A.

References: 1: How to Create Symbolic Links in Linux [Complete Guide] - Linux Handbook 2: Ln Command in Linux (Create Symbolic Links) | Linuxize 3: How to Create and Use Symbolic Links (aka Symlinks) on Linux - How-To Geek 4: Symbolic Links in Unix/Linux - Stack Abuse

The tar command is used to create or extract compressed archive files on BSD systems. It can handle various compression formats, such as gzip, bzip2, xz, and lzma. The tar command takes different options to specify the compression type, such as -z for gzip, -j for bzip2, -J for xz, and -Z for lzma. The other options are not related to compression, but to other functions of the tar command, such as -x for extracting, -c for creating, and -v for verbose output. References:

• [tar(1) - OpenBSD manual pages]
• [FreeBSD Handbook - Chapter 3. Unix Basics]
• [FreeBSD Handbook - Chapter 18. Storage]

This command and option can be used to perform a reverse DNS lookup, which is the process of finding the domain name or hostname associated with an IP address. The dig command is a tool that can query DNS servers for various types of records, such as A, MX, NS, PTR, etc. The -x option tells dig to perform a reverse DNS lookup by sending a PTR query to the DNS server. For example, to perform a reverse DNS lookup for the IP address 8.8.8.8, the following command can be used:

dig -x 8.8.8.8

The output of this command will show the PTR record for 8.8.8.8, which is dns.google. This means that the hostname for 8.8.8.8 is dns.google. Reverse DNS lookups are useful for verifying the identity of a host, checking for mail server configuration, or troubleshooting network problems

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

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 find command is used to search for files and directories that match certain criteria. The - -type option specifies the type of file to look for, and the d argument means directories. The . argument means the current directory. Therefore, the command find - -type d searches for all directories within the current directory. The other options are either invalid or do not match the question. References: 1: https://www.comptia.org/training/books/a-core-1-220-1101-study-guide, page 301  2: https://www.howtogeek.com/771399/how-to-use-the-find-command-in-linux/, section “The Linux find Command”

Compiling an application from source code allows for customization of the binary to a system’s particular needs, including optimization for specific hardware and enabling or disabling certain features. Pre-compiled binaries are quick and easy to install but they don’t allow for such customization.

References:

• Understand the difference between a pre-compiled binary and compiling from source

 The sysrc command is used in FreeBSD and NetBSD to manage system-wide daemon and service settings, including those that are started at boot time. It allows administrators to safely edit system rc files, such as /etc/rc.conf, where services to be started at boot time are specified1.

References:

• FreeBSD Handbook - rc.conf
• FreeBSD Man Pages - sysrc

The correct configuration line for sending all messages from the auth facility to a remote syslog server is auth.* @logger.example.org. In syslog configuration, the auth.* specifies the facility and priority, where auth is the facility for security/authorization messages, and * represents all priorities. The @ symbol is used to indicate that the messages are to be sent to a remote server, followed by the hostname of the remote syslog server. References:

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

The command pkg upgrade is used to update FreeBSD packages to newer versions. It compares the versions of installed packages with those in the repositories and performs upgrades as necessary. The pkg update command is used to update the repository catalog, but it does not perform the actual package upgrades1.

References:

• FreeBSD Handbook - Packages and Ports

The umask command in BSD is used to set default permissions for files or directories the user creates1. The umask value is permissions to deny, taken off whatever permissions would be given by default2. The default permission values for files are 666 (rw-rw-rw-), meaning read and write for user, group, and others3. The umask value of 022 means that the permissions to deny are 022 (—w–w-), meaning write for group and others. To calculate the default permissions for newly created files, we need to subtractthe umask value from the default permission value, using bitwise AND operation4. For example:

666 - 022 = 644 rw-rw-rw- - —w–w- = rw-r–r–

Therefore, the default permissions for newly created files with a umask of 022 are 644 (rw-r–r–), meaning read and write for user, and read for group and others.

References: 1: Umask command in Linux with examples - GeeksforGeeks 2: Different permission between directory and file with ‘umask’ - Unix & Linux Stack Exchange 3: Default File Permissions (umask) - docs.oracle.com 4: What is Umask and How to Use It {Update Default Linux File Permissions} - phoenixNAP KB

The command pkg_add is used to install binary packages on OpenBSD systems. It is a utility for installing and upgrading software packages from binary files. When using pkg_add, the system will fetch and install the specified package, along with any dependencies it may have123.

References:

• OpenBSD manual pages - packages(7)
• nixCraft - OpenBSD install or add binary software package using pkg_add

The /etc/fstab file contains information about the file systems that are mounted automatically at boot time or by the mount command. The file has six fields separated by whitespace: device, mount point, file system type, mount options, dump frequency, and pass number. The correct answer is D because it specifies the device (/dev/cd0a), the mount point (/cdrom), the file system type (cd9660), the mount option (ro for read-only), and the dump frequency and pass number (both 0 for no backup or fsck). The other answers are incorrect because they either have the wrong syntax, the wrong order of fields, or the wrong file system type. References:

• BSD Specialist Exam 702 Objectives, Topic 715: Basic Unix Skills, 715.2 File and Directory Management
• FreeBSD Handbook, Chapter 3: FreeBSD Basics, 3.8.2 Mounting and Unmounting File Systems

The -e option of the crontab command opens the current user’s crontab in an editor. The editor used is determined by the environment variables VISUAL or EDITOR. If neither of these variables is set, the default editor is vi. The user can edit the crontab file to add, modify, or delete cron jobs, which are scheduled commands or scripts that run at a specified time or interval. The crontab file has the following format:

minute hour day-of-month month day-of-week command

Each field can be a number, a range, a list, or an asterisk (*), which means all possible values. The command can be any valid shell command or script. For example, the following crontab entry runs the backup.sh script every day at 2:30 AM:

30 2 * * * /home/user/backup.sh

To save and install the crontab file, the user needs to exit the editor. The crontab command will check the syntax of the file and report any errors. If the file is valid, it will be installed and the cron daemon will execute the cron jobs according to the schedule. References:

• crontab(1) - Linux manual page
• FreeBSD Handbook: 11.6. Scheduling Tasks

In FreeBSD, theunamecommand is used to display system information. The option-vspecifically displays the version of the running operating system. This information is critical for system administrators and users who need to know the exact version of the OS they are working with, particularly when troubleshooting, updating, or configuring the system for specific software requirements.

https://man.freebsd.org/cgi/man.cgi?query=uname &sektion=1&format=html

The -v or --version option of the uname command displays the version level of the operating system. This is a string that identifies the release date and patch level of the system. For example, on FreeBSD, the output would be something like:

FreeBSD 13.0-RELEASE-p4 #0: Tue Aug 24 07:12:34 UTC 2021

This indicates that the system is running FreeBSD 13.0, with the fourth patch applied, and that the kernel was built on August 24, 2021. The version level can be useful to determine the compatibility and security of the system, as well as to report bugs or issues.

The file /etc/hostname.em0 contains the configuration for the network interface em0 on an OpenBSD system. This file specifies the IP address, netmask, gateway, and other options for the interface. The file is read by the netstart script during boot or when the interface is restarted. The file name is derived from the interface name, which is usually based on the driver name and the device number. For example, em0 is the first interface using the em driver, which supports Intel PRO/1000 network adapters.

References:

• Networking | OpenBSD Handbook
• [hostname.if(5) - OpenBSD manual pages]