702-100 Linux Professional Institute BSD Specialist Questions and Answers

The ports collection on FreeBSD is a package management system that allows users to install third-party software from source or binary packages. The ports collection is stored in the /usr/ports/ directory, which contains subdirectories for different categories of software, such as archivers, databases, editors, etc. Each subdirectory contains one or more ports, which are directories that contain the files needed to build and install the software. The /usr/ports/ directory can be updated with the portsnap command34

Binary packages are pre-compiled versions of the ports that can be installed with the pkg command. Binary packages are downloaded from the FreeBSD package repository,which is hosted at pkg.freebsd.org. The packages are installed in the /usr/local/ directory by default, and the information about the installed packages is stored in the /usr/local/pkg/ directory. The /usr/local/pkg/ directory contains files with the .db extension, which are SQLite databases that store the metadata of the packages. The pkg command can query and manipulate these databases56 References: 3: https://docs.freebsd.org/en/books/handbook/ports/  4: https://www.freebsd.org/ports/  5: https://docs.freebsd.org/en/books/handbook/pkgng-intro/  6: https://www.freebsd.org/cgi/man.cgi?query=pkg &sektion=8

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 wq! command is used to save a file and quit the vi editor, even if the file is read-only. The w command means write, the q command means quit, and the ! command means force. By combining these commands, the vi editor will override the file permissions and save the changes to the file, then exit the editor. The other options are either invalid syntax or do not force the write operation. For example, wq will save and quit only if the file is writable, ql will quit without saving, and fw! will force write but not quit. References:

• [vi] - FreeBSD vi(1) Manual Page
• [wq!] - How to save a file in vi / vim editor in Linux / Unix

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 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 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 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]

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

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 subnet mask 255.255.224.0 corresponds to the hexadecimal netmask 0xffffe000 shown in the output. This subnet mask indicates a subnet with 19 bits for the network portion and 13 bits for the host portion, allowing for a large number of hosts within the subnet.

References:

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

The name of the NetBSD installation program is sysinst. It is the standard installer used by NetBSD for setting up the system on a new machine. The sysinst program guides users through the installation process, including disk partitioning, package selection, and system configuration45.

References:

• NetBSD Guide - Example installation
• NetBSD Guide - Installing NetBSD: Preliminary considerations and preparations

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 adduser.conf file is used to store the default settings for the interactive adduser script on BSD systems. The adduser script is a shell script that uses the pw command to add new users to the system. It creates passwd/group entries, a home directory, copies dotfiles and sends the new user a welcome message. The adduser.conf file allows the administrator to pre-set certain configuration options, such as the default shell, home partition, login group, encryption method, etc. The other options are either invalid files or belong to other purposes. For example, login.conf is used to define login classes, pw.conf is used to configure the pw command, user.conf is used to set user-specific kernel variables, and usermgmt.conf is used to configure user management utilities. References:

• adduser - FreeBSD adduser(8) Manual Page1
• adduser.conf - FreeBSD adduser.conf(5) Manual Page2
• [pw] - FreeBSD pw(8) Manual Page

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 /etc/printcap file on a BSD system defines the printers that are available by the Ipr printing system. The Ipr printing system is a BSD-compatible printing system that uses the lpd daemon to manage print jobs and spooling. The /etc/printcap file contains a series of entries, one for each printer, that specify the printer name, device, options, and filters. The format and syntax of the /etc/printcap file are described in the printcap(5) manual page. References:

• About Printing on FreeBSD | The FreeBSD Forums
• The BSD Printing Protocol (System Administration Guide, Volume 2) - Oracle
• Chapter 11. Printing | FreeBSD Documentation Portal