LPI 010-160 Linux Essentials Certificate Exam - version 1.6 Exam Practice Test

The last command in Linux is used to display the list of all the users logged in and out since the file /var/log/wtmp was created1. The output of the last command shows the username, the terminal, the IP address, the login time and date, and the duration of the session for each record2. The option E is the only one that matches this format. Theother options are not related to the last command. Option A shows a list of commands executed by a user. Option B shows the password change information for a user. Option C shows the last login information for a user. Option D shows the mount information for a filesystem. References:

• Linux Essentials Version 1.6 Objectives3, Topic 1.4: Command Line Basics, Subtopic: Basic Shell Commands
• Linux last Command Tutorial for Beginners (8 Examples)4
• Linux Essentials Version 1.6 Exam Preparation Guide, Section 1.4: Command Line Basics, Page 16

RPM stands for RPM Package Manager (formerly known as Red Hat Package Manager), which is a powerful, command-line package management tool developed for the Red Hat operating system. It is now used as a core component in many Linux distributions such as CentOS, Fedora, Oracle Linux, openSUSE and Mageia1. RPM can install, uninstall,and query individual software packages, but it cannot manage dependency resolution like YUM2. YUM is another package management tool that is based on RPM and can handle dependencies automatically. YUM is the primary package management tool for installing, updating, removing, and managing software packages in Red Hat Enterprise Linux2. Therefore, the correct answer is B. rpm, as it is the underlying package management tool used in Red Hat-based Linux systems. References:

• Linux package management with YUM and RPM | Enable Sysadmin
• Chapter 13. Package Management Tool Red Hat Enterprise Linux 5 | Red Hat Customer Portal
• Difference Between YUM and RPM | 2DayGeek

 Ubuntu Linux LTS and Red Hat Enterprise Linux are two Linux distributions that meet the requirements of hosting services for a period of several years and receiving important security updates from their Linux distribution. LTS stands for Long Term Support, which means that these versions of Ubuntu Linux are supported by Canonical, the company behind Ubuntu, for five years with security patches, bug fixes, and software updates1. Red Hat Enterprise Linux is a commercial Linux distribution that offers a stable and secure platform for enterprise applications, with a 10-year life cycle and regular security updates from Red Hat, the company behind RHEL2. Fedora Linux, Debian GNU/Linux Unstable, and Ubuntu Linux non-LTS are not suitable for the requirements, because they have shorter support cycles and are more focused on providing the latest features and software versions, rather than stability and security. Fedora Linux releases a new version every six months and each version is supported for 13 months3. Debian GNU/Linux Unstable is the development branch of Debian, which is constantly updated with new packages and changes, but is not intended for production use4. Ubuntu Linux non-LTS releases a new version every six months and each version is supported for nine months1. References:

• Ubuntu release cycle | Ubuntu
• Red Hat Enterprise Linux Life Cycle - Red Hat Customer Portal
• Fedora Release Life Cycle - Fedora Project Wiki
• Debian Unstable - Debian Wiki

The execute bit in Linux is a permission bit that allows the user to run an executable file or enter a directory. For regular files, such as scripts or binaries, the execute bit must be set for the user to run them. For directories, the execute bit allows the user to access the files and subdirectories inside. Therefore, to successfully execute the script test.sh, the execute bit should be set in the file’s permissions. This can be done by using the chmod command with the +x option, for example: chmod +x test.sh. The other options are either irrelevant or incorrect. The file’s extension does not affect its executability, only its association with a program. The user executing the script does not need to be in the exec group, as long as the user has the execute permission on the file. The SetUID bit is a special permission bit that allows the user to run the file as the file’s owner, regardless of the user’s identity. This is not necessary for executing the script, and may pose a security risk. The #!./test.sh syntax is invalid, as the #! is used to specify the interpreter for the script, not the script itself. References:

• Linux Essentials Version 1.6 Objectives1, Topic 1.4: Command Line Basics, Subtopic: Basic Shell Commands
• Linux Essentials Version 1.6 Exam Preparation Guide2, Section 1.4: Command Line Basics, Page 16
• Execute vs Read bit. How do directory permissions in Linux work?3

 The reason why the script.sh does not display the content of the variable MYVAR is that the variable is not exported to the environment of the script. When a script is executed, it runs in a separate process that inherits the environment variables from the parent process, but not the shell variables. A shell variable is a variable that is defined and visible only in the current shell session, while an environment variable is a variable that is exported to the environment and visible to all processes that run in that environment1.

To make a shell variable an environment variable, we need to use the export command. The export command takes a shell variable name and adds it to the environment of the current shell and any subshells or processes that are created from it2. For example, to export the variable MYVAR with the value value, we can use:

export MYVAR=value

This will make the variable MYVAR available to the script.sh when it is executed, and the script will print the value of MYVAR as expected. Alternatively, we can also use the export command with the -n option to remove a variable from the environment, or with the -p option to list all the environment variables2.

The other options are not valid ways to set MYVAR as an environment variable. The !MYVAR=value option is not a valid syntax for setting a variable in bash. The env MYVAR=value option will run the env command with the MYVAR=value argument, which will print the environment variables with the addition of MYVAR=value, but it will not affect the current shell or the script.sh3. The MYVAR=value option will set MYVAR as a shell variable, but not as an environment variable, so it will not be visible to the script.sh1. The $MYVAR=value option will try to set the variable whose name is the value of MYVAR to the value value, which is not what we want4. References:

• Linux Essentials Exam Objectives, Version 1.6, Topic 103.1, Weight 2
• Linux Essentials Certification Guide, Chapter 3, Page 51-52
• env(1) - Linux manual page
• Bash Variables - LinuxConfig.org

The tar command in Linux is used to create, extract, list, and manipulate archive files1. The -c option tells the command to create a new archive file. The -f option specifies the name of the archive file. The last argument is the name of the directory or file to be archived. Therefore, the command tar -cf work.tar ./work/ will create an archive file named work.tar from the contents of the directory ./work/. The other options are either invalid or do not create the desired archive file. Option A uses an unrecognized option --new. Option C uses an incorrect option --content and an incorrect extension .tgz for a plain tar archive. Option D and E use an incorrect syntax for redirecting the input or output of the tar command. References:

• Linux Essentials Version 1.6 Objectives, Topic 1.4: Command Line Basics, Subtopic: Basic Shell Commands
• Linux Essentials Version 1.6 Exam Preparation Guide, Section 1.4: Command Line Basics, Page 16
• Tar Command in Linux (Create and Extract Archives) | Linuxize2

The general structure of a for loop in a shell script is as follows12:

for variable in list do commands done

The variable is the name of a loop counter or iterator that takes on the values of the items in the list. The list can be a sequence of words, numbers, filenames, or the output of a command. The commands are the body of the loop that are executed for each value of the variable. The do and done keywords mark the beginning and the end of the loop body.

The option C. for file in *.txt do echo $i done follows this structure, with the variable being file, the list being *.txt (which matches all the files with the .txt extension in the current directory), and the command being echo $i (which prints the value of the variable i, which is presumably set somewhere else in the script).

The other options are incorrect because:

• A. for *.txt as file => echo $file uses an invalid syntax for a for loop. The as keyword is not part of the shell script syntax, and the => symbol is not a valid operator. The correct way to write this loop would be:

for file in *.txt do echo $file done

• B. for *.txt ( echo $i ) uses an invalid syntax for a for loop. The parentheses are not part of the shell script syntax, and the loop body is missing the do and done keywords. The correct way to write this loop would be:

for i in *.txt do echo $i done

• D. for ls *.txt exec {} ; uses an invalid syntax for a for loop. The ls command is not a valid variable name, and the exec {} ; is not a valid command. This looks like a mix of a for loop and a find command. The correct way to write this loop would be:

for file in *.txt do exec $file done

• E. foreach @{file} { echo $i } uses an invalid syntax for a for loop. The foreach keyword is not part of the shell script syntax, and the @{file} and { echo $i } are not valid expressions. This looks like a mix of a for loop and a Perl syntax. The correct way to write this loop would be:

for file in * do echo $file done

References:

• Looping Statements | Shell Script - GeeksforGeeks
• How do I write a ‘for’ loop in Bash? - Stack Overflow

 In Linux, every file and directory is associated with an owner and a group. The owner is the user who created the file or directory, and the group is the group to which the owner belongs. Therefore, each file is owned by exactly one user and one group. This is true for option A. The other options are false for the following reasons:

• Option B: The owner of a file does not always have full permissions when accessing the file. The permissions are determined by the file mode, which can be changed by the owner or the root user. The file mode specifies the read, write, and execute permissions for the owner, the group, and others. The owner can have different permissions than the group or others.
• Option C: The user owning a file does not have to be a member of the file’s group. The owner can change the group ownership of the file to any group on the system, regardless of whether the owner belongs to that group or not. However, only the root user or a user with the CAP_CHOWN capability can change the group ownership to a group that the owner is not a member of.
• Option D: When a user is deleted, all files owned by the user do not disappear. The files remain on the system, but their owner is changed to an invalid user ID (UID). The files can still be accessed by the group or others, depending on the permissions. The files can also be reclaimed by the root user or a user with the CAP_CHOWN capability, who can change the owner to a valid user.
• Option E: The owner of a file can be changed once it is assigned to an owner. The owner can transfer the ownership to another user, or the root user or a user with the CAP_CHOWN capability can change the owner to any user on the system. The command to change the owner of a file is chown. References: 1: Chown Command in Linux (File Ownership) | Linuxize 2 3: Linux File Permissions and Ownership Explained with Examples 4 2: 3 Ways to Find File Owner in Linux - howtouselinux 1

 A private web browser window is a mode of browsing that prevents the browser from saving your browsing history, cookies, and other site data, or information entered in forms. However, it does not prevent websites, your employer or school, or your internet service provider from tracking your online activity. The main differences between a private web browser window and a regular web browser window are:

• Private web browser windows do not store cookies persistently. Cookies are small files that websites use to store information on your device, such as your preferences, login status, or tracking data. In a regular web browser window, cookies are stored until they expire or you delete them. In a private web browser window, cookies are deleted when you close all private windows.
• Private web browser windows do not keep records in the browser history. The browser history is a list of web pages that you have visited in the past. In a regular web browser window, the browser history is saved and can be accessed by anyone who uses the same device or profile. In a private web browser window, the browser history is not saved and cannot be viewed by anyone.
• Private web browser windows do not send regular stored cookies. When you visit a website in a regular web browser window, the browser sends any cookies that are stored for that website. This allows the website to recognize you and provide personalized content or services. When you visit a website in a private web browser window, the browser does not send any cookies that are stored in regular windows. This prevents the website from identifying you or linking your activity across different sessions.

References: Browse in private - Computer - Google Chrome Help, Browse InPrivate in Microsoft Edge - Microsoft Support, Private Browsing: What Is It and How to Use It | Edge Learning Center

 The DNS record types that hold an IP address are the A and AAAA records. These records are used to map a domain name to an IP address of the host, which is necessary for establishing a connection between a client and a server. The A record holds a 32-bit IPv4 address, while the AAAA record holds a 128-bit IPv6 address. For example, the A record for www.example.com could be:

www.example.com. IN A 192.0.2.1

This means that the domain name www.example.com resolves to the IPv4 address 192.0.2.1. Similarly, the AAAA record for www.example.com could be:

www.example.com. IN AAAA 2001:db8::1

This means that the domain name www.example.com resolves to the IPv6 address 2001:db8::1.

The other options are incorrect because:

• NS records are used to specify the authoritative name servers for a domain. They do not hold an IP address, but a domain name of the name server. For example, the NS record for example.com could be:

example.com. IN NS ns1.example.com.

This means that the name server ns1.example.com is authoritative for the domain example.com.

• MX records are used to specify the mail exchange servers for a domain. They do not hold an IP address, but a domain name of the mail server and a preference value. For example, the MX record for example.com could be:

example.com. IN MX 10 mail.example.com.

This means that the mail server mail.example.com has a preference value of 10 for receiving email for the domain example.com.

• CNAME records are used to create an alias for a domain name. They do not hold an IP address, but another domain name that the alias points to. For example, the CNAME record for www.example.com could be:

www.example.com. IN CNAME example.com.

This means that the domain name www.example.com is an alias for the domain name example.com.

References:

• DNS Record Types: Defined and Explained - Site24x7
• List of DNS record types - Wikipedia

The sort command is used to sort the lines of a file or a stream of input according to a specified criterion, such as alphabetical order, numerical order, reverse order, etc. By default, the sort command sorts the lines in ascending alphabetical order, using the firstcharacter of each line as the key. For example, the command sort data.csv will sort the lines of the file data.csv in alphabetical order and display the output on the screen. If you want to save the sorted output to a new file, you can use the redirection operator (>) to specify the output file name. For example, the command sort data.csv > sorted_data.csv will sort the lines of the file data.csv in alphabetical order and save the output to a new file named sorted_data.csv. The other commands are either invalid or do not perform the sorting operation. The a…z command does not exist, the abc command is a text editor, the wc command counts the number of words, lines, and bytes in a file, and the grep command searches for a pattern in a file or a stream of input. Therefore, the correct answer is B. References:

• Linux Essentials - Linux Professional Institute (LPI), section 2.3.2
• LPI Linux Essentials Study Guide: Exam 010 v1.6, 3rd Edition, chapter 4, page 95.

The zip command is used to create compressed archive files that can contain one or more files or directories. The zip command takes the name of the archive file as the first argument, followed by the names of the files or directories to be included in the archive. You can also use wildcards to match multiple files or directories with a common pattern. For example, the command zip poems.zip *.txt will create the ZIP archive poems.zip containing all files in the current directory whose names end in .txt. The other commands are either invalid or do not perform the desired operation. The command zip *.txt > poems.zip will try to create an archive for each file ending in .txt and redirect the output to poems.zip, which is not a valid archive file. The command zcat *.txt poems.zip will try to decompress and concatenate the contents of the files ending in .txt and poems.zip, which is not a valid ZIP file. The command zip cfz poems.zip *.txt will fail because the options c, f, and z are not valid for the zip command. The command cat *.txt | zip poems.zip will try to read the contents of the files ending in .txt from the standard input and create an archive named poems.zip, but this will not preserve the file names or attributes of the original files. References:

• Linux Essentials - Linux Professional Institute (LPI), section 3.1.1
• 3.1 Archiving Files on the Command Line - Linux Professional Institute Certification Programs, slide

The distribution’s package repository is the preferred source for the installation of new applications in a Linux based operating system. A package repository is a collection of software packages that are maintained by the distribution and can be easily installed, updated, or removed using a package manager. Package repositories offer several advantages, such as:

• They ensure compatibility and stability with the system and other packages.
• They provide security updates and bug fixes for the packages.
• They reduce the risk of malware or corrupted files.
• They simplify the dependency management and configuration of the packages.

The other sources are not preferred because they may not offer these benefits and may cause problems with the system. The vendor’s version management system, the vendor’s website, or a CD-ROM disk may contain packages that are not compatible with the distribution or may conflict with other packages. A retail store may not have the latest or the most suitable packages for the system. References:

• Linux Essentials - Linux Professional Institute (LPI), section 1.3 Installing, Updating and Removing Software Packages
• LPI Linux Essentials Study Guide: Exam 010 v1.6, 3rd Edition, chapter 4 Working on the Command Line, section 4.2 Managing Software
• Table of Contents - Linux Professional Institute Certification Programs, section 1.3 Installing, Updating and Removing Software Packages

CentOS is a Linux distribution that is based on the source code of Red Hat Enterprise Linux (RHEL). It is a free and open-source community-supported OS that provides an enterprise-level computing platform. CentOS is fully compatible with RHEL and can run the same applications and packages. Therefore, CentOS allows the team members to apply as much of their Red Hat Enterprise Linux knowledge as possible for their hobby project. References:

• Linux Essentials Version 1.6 Objectives1, Topic 1.1: Linux Evolution and Popular Operating Systems, Subtopic: Linux Distributions
• Linux Essentials Version 1.6 Exam Preparation Guide2, Section 1.1: Linux Evolution and Popular Operating Systems, Page 7
• CentOS Website3, About CentOS Linux
• Red Hat Enterprise Linux derivatives - Wikipedia4

A Linux distribution is a collection of software that is based on the Linux kernel and can be installed on a computer or a device to create a functional operating system. A Linux distribution typically includes the Linux kernel, a set of system utilities and libraries, a graphical user interface (GUI), a package manager, and various applications and services. A Linux distribution may also include additional software or features that are specific to the distribution’s goals, target audience, or philosophy. For example, some Linux distributions are designed for desktop users, while others are optimized for servers, embedded systems, or security. Some Linux distributions are based on other Linux distributions, while others are developed independently. Some Linux distributions are free and open source, while others are proprietary or commercial. Some Linux distributions are popular and widely used, while others are niche or experimental. Some examples of Linux distributions are Ubuntu, Fedora, Debian, Mint, Arch, and Red Hat. References:

• Linux Essentials Topic 101: System Architecture, section 101.1: Determine and configure hardware settings.
• Linux Essentials Topic 102: Linux Installation and Package Management, section 102.1: Design hard disk layout.
• Linux Essentials Topic 103: GNU and Unix Commands, section 103.1: Work on the command line.
• Linux Essentials Topic 104: The Linux Operating System, section 104.1: Boot the system.
• Linux Essentials Topic 105: The Power of the Command Line, section 105.1: Use text streams and filters.
• Linux Essentials Topic 106: Security and File Permissions, section 106.3: Modify file and directory permissions.
• What is a Linux distribution? - Linux.com
• Linux distribution - Wikipedia
• Best Linux Distributions For Everyone in 2023 - It’s FOSS

A symbolic link, also known as a symlink or soft link, is a special type of file that points to another file or directory by its name. A symbolic link can point to a file or directory on the same or different file system, as long as the target is accessible. For example, you can create a symbolic link to a file on a USB drive or a network share, as long as the device is mounted or the connection is established. However, if the target of the symbolic link is moved, renamed, or deleted, the link becomes broken and does not work. To create a symbolic link, you can use the ln command with the -s or --symbolic option, followed by the target name and the link name. For example, ln -s /mnt/usb/file.txt link.txt creates a symbolic link named link.txt that points to the file.txt on the USB drive mounted at /mnt/usb.

The other options are not true about links in a Linux file system. A symbolic link can point to a directory as well as a file. A hard link, which is a direct reference to the same data as another file, can only point to a file and not a directory. A hard link cannot span across different file systems, because it depends on the inode number, which is unique within a file system. When the target of the symbolic link is moved, the link is not automatically updated, but becomes broken. Any user can create hard links, as long as they have the permission to read and write the target file and the link directory.

References:

• Linux Essentials - Linux Professional Institute (LPI)
• Ln Command in Linux (Create Symbolic Links) | Linuxize

 The /usr/share/doc/ directory is the standard location for documentation files for installed software packages on Linux systems12. It contains subdirectories for each package, which may include README files, manuals, license information, changelogs, examples, and other useful resources12. The /usr/share/doc/ directory is part of the Filesystem Hierarchy Standard (FHS), which defines the structure and layout of files and directories on Linux and other Unix-like operating systems3.

The other options are incorrect because:

• /etc/defaults/ is a directory that contains settings for userland applications or services/daemons4.
• /var/info/ is not a standard directory on Linux systems. The /var/ directory is used for variable data files, such as logs, caches, spools, and temporary files3.
• /doc/ is not a standard directory on Linux systems. The / directory is the root of the filesystem hierarchy and contains essential files and directories for booting, restoring, recovering, and/or repairing the system3.
• /usr/examples/ is not a standard directory on Linux systems. The /usr/ directory is used for shareable, read-only data, such as binaries, libraries, documentation, and source code3.

References:

• Linux configuration: Understanding *.d directories in /etc | Enable Sysadmin
• Configuration Files in Linux | Baeldung on Linux
• Filesystem Hierarchy Standard - Wikipedia
• Which of the Following Directories Contains Information, Documentation …

The host command is used to resolve a DNS name to an IP address or vice versa. It can also perform other DNS queries, such as finding the mail servers for a domain. The host command has the following syntax: host [options] [name] [server]. The name argument can be a hostname, such as www.lpi.org, or an IP address, such as 192.168.0.1. The server argument is optional and specifies the name or IP address of the DNS server to query. If no server is given, the default system resolver is used.  References:

• Linux Essentials Version 1.6 Objectives: 1.4.1. Demonstrate an understanding of the purpose and types of DNS records1
• Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Chapter 10. Network Fundamentals - 10.3. DNS and Hostname Resolution - 10.3.1. The host Command2
• Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Appendix A. Answers to the Exercises - Chapter 10. Network Fundamentals - 10.3. DNS and Hostname Resolution - Exercise 10.3.12

A process ID on Linux is a unique integer value that identifies a running process. The process ID can range from 0 to a maximum limit, which is usually 32768 or higher, depending on the system configuration. The process ID of 0 is reserved for the kernel’s idle task, and the process ID of 1 is reserved for the init system, which is the first process launched by the kernel. The process IDs are assigned sequentially to new processes, and are recycled when a process terminates. Therefore, the only valid value for a process ID among the given options is 21398, which is an integer within the possible range. The other values are not valid process IDs because they are either strings, hexadecimal numbers, or file paths, which do not match the format of a process ID on Linux. References:

• Linux Essentials - Linux Professional Institute (LPI)
• How Are Linux PIDs Generated? | Baeldung on Linux

 A bus is a communication system that transfers data between components inside a computer or between computers. There are different types of buses that serve different purposes. The RAM bus connects the CPU with the main memory, the NUMA bus connects multiple processors in a multiprocessor system, the CPU bus connects the CPU with other components on the motherboard, and the Auto bus is a fictional bus that can transform into a robot. The SATA bus is the correct answer because it is a type of bus that can connect hard disk drives with the motherboard. SATA stands for Serial Advanced Technology Attachment and it is a standard interface for connecting storage devices such as hard disk drives, solid state drives, and optical drives. SATA offers faster data transfer rates, lower power consumption, and improved cable management compared to older interfaces such as IDE and SCSI. References: : [Bus (computing)] : [Transformers: Robots in Disguise (2015 TV series)] : [Serial ATA]3) : [SATA vs. IDE: What’s the Difference?]

The grep command is used to search for a pattern in a file or input. The -i option makes the search case-insensitive, meaning that it will match both uppercase and lowercase letters. The grep command takes the pattern as the first argument and the file name as the second argument. Therefore, the command grep -i linux operating-systems.txt will find all lines in the file operating-systems.txt which contain the term linux, regardless of the case. References: Linux Essentials - Topic 103: Finding Linux Documentation and Linux Essentials - Topic 104: Command Line Basics

The shell script uses a for loop to iterate over the files that match the pattern *.txt in the current directory. The pattern *.txt means any file name that ends with .txt, regardless of the case. The loop body simply prints the value of the variable file, which holds the name of the current file in each iteration. Therefore, the output of the shell script would be the names of the files that end with .txt, one per line. In this case, the files are A.txt and b.txt, so the output would be:

A.txt b.txt

This corresponds to option E. The other options are incorrect for the following reasons:

• Option A: *.txt is not the output of the shell script, but the pattern that the loop uses to match the files. The shell expands the pattern to the actual file names before executing the loop.
• Option B: a and b are not the names of the files, but the first characters of the file names. The loop prints the whole file name, including the extension.
• Option C: c.cav is not a file that matches the pattern *.txt, because it has a different extension. The loop ignores files that do not end with .txt.
• Option D: A.txt is only one of the files that matches the pattern *.txt, but not the only one. The loop prints both A.txt and b.txt.

References: 1: 9 Examples of for Loops in Linux Bash Scripts - How-To Geek 2 3: Looping Statements | Shell Script - GeeksforGeeks 1 4: shell - Loop through all the files with .txt extension in bash - Stack Overflow 5

The return value of a shell script after successful execution is 0. This is a convention followed by most UNIX and Linux commands, programs, and utilities. A return value of 0 indicates that the command or script completed successfully, without any errors. A return value of non-zero (1-255) indicates that the command or script failed, and the value can be interpreted as an error code. The return value of a command or script is stored in the special variable $? and can be used to test the outcome of a command or script123. For example, the following script will print a message based on the return value of the ls command:

#!/bin/bash ls if [ $? -eq 0 ]; then echo “ls command executed successfully” else echo “ls command failed” fi

References: 1: Exit and Exit Status - Linux Documentation Project 2: Linux Passwd Command Help and Examples 3: bash - Which is the best way to check return result? - Unix & Linux Stack Exchange