LPI 702-100 - Linux Professional Institute BSD Specialist

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 date command in BSD systems provides the following features:

It outputs the time in a specific format. The date command can display the current date and time in various formats, depending on the options and arguments given. For example, the command date +%Y-%m-%d will output the date in the format of year-month-day, such as 2023-04-30. The command date +%T will output the time in the format of hour:minute:second, such as 22:51:42. The command date +%A will output the full name of the weekday, such as Thursday. The date command supports many formatting characters that can be used to customize the output. For a full list of formatting characters, see the date(1) manual page1.

It sets the clock to a specific time. The date command can also be used to set the system date and time, if the user has the appropriate privileges. For example, the command date 0430225123 will set the date and time to April 30, 2023, 22:51:42. The command date -u 0430225123 will set the date and time to the same value, but in UTC (Coordinated Universal Time) instead of the local time zone. The command date -n will set the date and time to the current network time, using the ntpd(8) daemon1.

The date command does not provide the following features:

It does not display a calendar. The date command only displays the date and time, not a calendar. To display a calendar, the cal(1) or ncal(1) commands can be used instead. For example, the command cal 4 2023 will display the calendar for April 2023. The command ncal -w 2023 will display the calendar for the whole year 2023, with week numbers23.

It does not send NTP queries. The date command does not send any network requests or queries to NTP (Network Time Protocol) servers. To synchronize the system clock with NTP servers, the ntpd(8) daemon or the ntpdate(8) utility can be used instead. For example, the command ntpd -q will query one or more NTP servers and adjust the system clock accordingly. The command ntpdate pool.ntp.org will set the date and time to the value returned by the NTP server pool.ntp.org45.

It does not change the system’s timezone. The date command does not change the system’s timezone setting, only the date and time values. To change the system’s timezone, the tzsetup(8) utility or the ln(1) command can be used instead. For example, the command tzsetup will run an interactive program that allows the user to select a timezone from a list of regions and cities. Thecommand ln -sf /usr/share/zoneinfo/Europe/Paris /etc/localtime will create a symbolic link from the file /etc/localtime to the file /usr/share/zoneinfo/Europe/Paris, which contains the timezone information for Paris, France . References:

date(1) - FreeBSD

cal(1) - FreeBSD

ncal(1) - FreeBSD

ntpd(8) - FreeBSD

ntpdate(8) - FreeBSD

[tzsetup(8) - FreeBSD]

[ln(1) - FreeBSD]

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 question mark (?) is a special character in regular expressions that modifies the preceding expression to match zero or one times. For example, the regular expression colou?r matches both color and colour, but not colouur or colr. The question mark is also used to make an expression non-greedy, meaning that it will match the shortest possible string instead of the longest. For example, the regular expression <.?> matches the first pair of angle brackets in a string, while <.> matches the entire string enclosed by the outermost pair of angle brackets. References:

Regular expression - Wikipedia, section “Basic concepts”

How to write Regular Expressions? - GeeksforGeeks, section “Special Characters”

The file command is used to determine the type of data contained in a computer file. It performs a series of tests on the file and prints a description of the file type based on the first successful test. The file command can take one or more file names as its arguments. For example, file mybackup will display the file type of mybackup. The other options are not valid commands for finding the file type. References:

file command in Linux with examples

file (command) - Wikipedia

Linux File Command

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 /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 zfs snapshot command creates a snapshot of a ZFS dataset, which is a point-in-time copy of the data. The snapshot name is specified as follows: filesystem@snapname or volume@snapname. The snapshot name must satisfy the naming requirements in ZFS Component Naming Requirements1. In this case, the command zfs snapshot space/data@snap1 creates a snapshot of the dataset space/data named snap1. The other options are either invalid or do not create a snapshot. References: 1:https://docs.oracle.com/cd/E19253-01/819-5461/gbcya/index.html