702-100 Exam Dumps - Linux Professional Institute BSD Specialist

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”

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 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

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

Nmap is a program that can be used to enumerate all responsive hosts on a subnet. Nmap stands for Network Mapper, and it is a tool that can perform network discovery, port scanning, service detection, vulnerability assessment, and more. Nmap can send different types of packets to probe the hosts on a subnet and determine which ones are alive and what services they are running. Nmap can also perform OS fingerprinting, which can identify the operating system of the target hosts. Nmap has many options and features that can customize the scan according to the user’s needs and preferences. The other programs are not suitable for enumerating all responsive hosts on a subnet, because:

• A. traceroute: This program is used to trace the route of packets from the source host to the destination host. It can show the intermediate hops and the latency of each hop. However, it cannot show all the hosts on a subnet, only the ones that are on the path to the destination.
• B. netstat: This program is used to display the status of network connections, routing tables, interface statistics, and more. It can show the local and remote addresses and ports of the active connections, but it cannot show all the hosts on a subnet, only the ones that are connected to the local host.
• D. rtso1: This is not a valid program name, but it may be a typo for rtso, which is a program that can perform TCP SYN scanning. However, this program is not as versatile and powerful as nmap, and it can only scan TCP ports, not UDP or other protocols.
• E. route: This program is used to manipulate the routing table, which is used to determine the next hop for a packet based on its destination address. It can show the destination, gateway, interface, and flags of each route, but it cannot show all the hosts on a subnet, only the ones that are reachable via a specific gateway. References: 6: https://nmap.org/book/man.html 7: https://www.freebsd.org/cgi/man.cgi?query=traceroute&sektion=8 : https://www.freebsd.org/cgi/man.cgi?query=netstat&sektion=1 : https://www.freebsd.org/cgi/man.cgi?query=rtso&sektion=1 : https://www.freebsd.org/cgi/man.cgi?query=route&sektion=8

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

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 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