Pass the LPI Linux Essentials 010-160 Questions and answers with ExamsMirror

The useradd command in Linux is used to create new user accounts on the system1. The -m option tells the command to create the user’s home directory as /home/username and copy the files from /etc/skel directory to the user’s home directory2. The /etc/skel directory contains the default configuration files for new users3. Therefore, the command useradd -m tux will add the new user tux and create the user’s home directory with default configuration files. The other options are either invalid or do not create the user’s home directory. 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

Linux useradd Command Tutorial for Beginners (15 Examples)

 The PATH environment variable is a colon-separated list of directories that the shell searches for commands. To add a new directory to the PATH, you need to append it to the existing value of the variable, using the syntax PATH=new/dir:PATH. However, this only changes the PATH for the current shell session. To make the change permanent, you need to use the export command, which makes the variable available to all child processes of the shell. The export command takes the name of the variable as an argument, without the dollar sign ($). Therefore, the correct command to add /new/dir/ to the PATH and export it is export PATH=/new/dir:PATH. References:

Linux Essentials - Linux Professional Institute (LPI)

How to set the path and environment variables in Windows - Computer Hope

The operator that matches the preceding character either zero or one time in a regular expression is the question mark (?). This operator is also known as the optional quantifier, because it makes the preceding character or group of characters optional. For example, the regular expression colou?r matches both color and colour, because the u is optional. The question mark can also be used to modify other quantifiers, such as * (zero or more), + (one or more), or {m,n} (between m and n times), to make them non-greedy, meaning they will match the shortest possible string instead of the longest. For example, the regular expression .*? matches any character zero or more times, but as few as possible. The question mark is one of the basic regular expression operators covered in the Linux Essentials certification program from the Linux Professional Institute (LPI). References:

Linux Essentials - Linux Professional Institute (LPI)

Regular Expressions:Difference between ‘optional occurrence’ and 'zero …

The -R parameter of the ls command prints a recursive listing of a directory’s content, meaning that it will list not only the files and directories in the current directory, but also the files and directories in all the subdirectories12. For example, if you have a directory structure like this:

/home/user/ ├── dir1 │ ├── file1 │ └── file2 └── dir2 ├── file3 └── file4

You can use the command ls -R /home/user/ to list all the files and directories recursively, and the output will look like this:

/home/user/: dir1 dir2

/home/user/dir1: file1 file2

/home/user/dir2: file3 file4

The -R parameter is also known as the --recursive option, which is the long form of the same parameter12. You can use either -R or --recursive to achieve the same result.

 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

Most commands on Linux can display information on their usage by running the command with the option -h or --help. This option shows a brief summary of the command syntax, options, arguments, and examples. For example, running ls -h or ls --help will display the usage information for the ls command, which lists files and directories. The -h or --help option is a standard convention for most Linux commands, and it is useful for learning how to use a command or checking its available options. However, some commands may not support this option, or may use a different option to display usage information. In that case, you can use the man command to access the manual page for the command, which provides more detailed information on the command usage, description, options, arguments, examples, and references. For example, running man ls will display the manual page for the ls command. The man command is one of the applications covered in the Linux Essentials certification program from the Linux Professional Institute (LPI). References:

Linux Essentials - Linux Professional Institute (LPI)

Linux Commands Cheat Sheet: Beginner to Advanced - GeeksforGeeks

The tar command is used to create or extract compressed archive files that contain multiple files or directories. The tar command has the following syntax: tar [options] [archive-file] [file or directory…]. The options argument specifies how the tar command should operate and what kind of compression should be used. The archive-file argument is the name of the archive file to be created or extracted. The file or directory argument is the name of one or more files or directories to be included in or extracted from the archive file.

The following are some of the common options for the tar command:

-c: create a new archive file.

-x: extract files from an existing archive file.

-t: list the contents of an archive file.

-v: show the progress of the operation.

-f: specify the name of the archive file.

-z: use gzip compression or decompression.

-j: use bzip2 compression or decompression.

-J: use xz compression or decompression.

The options -z and -j are used to handle compression with the tar command. The option -z uses the gzip program to compress or decompress the archive file, which usually has the extension .tar.gz or .tgz. The option -j uses the bzip2 program to compress or decompress the archive file, which usually has the extension .tar.bz2 or .tbz. Both gzip and bzip2 are popular compression programs that reduce the size of files by removing redundant or unnecessary information.

For example, to create a compressed archive file called backup.tar.gz that contains the files and directories in the current directory, the following command can be used:

tar -czvf backup.tar.gz .

To extract the files and directories from the archive file backup.tar.gz to the current directory, the following command can be used:

tar -xzvf backup.tar.gz

To create a compressed archive file called backup.tar.bz2 that contains the files and directories in the current directory, the following command can be used:

tar -cjvf backup.tar.bz2 .

To extract the files and directories from the archive file backup.tar.bz2 to the current directory, the following command can be used:

tar -xjvf backup.tar.bz2

The other options in the question are not related to compression. The option -bz is invalid, as there is no such option for the tar command. The option -g is used to create or update an incremental archive file, which only contains the files that have changed since the last backup. The option -z2 is also invalid, as there is no such option for the tar command. References:

Linux Essentials Version 1.6 Objectives: 3.1. Archiving Files on the Command Line1

Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Chapter 9. The Power of the Command Line - 9.1. Archiving Files on the Command Line - 9.1.1. The tar Command2

Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Appendix A. Answers to the Exercises - Chapter 9. The Power of the Command Line - 9.1. Archiving Files on the Command Line - Exercise 9.1.12

The correct command to create an archive file work.tar from the contents of the directory ./work/ is tar –cf work.tar ./work/. This command uses the -c option to create a new archive, the -f option to specify the file name, and the ./work/ argument to indicate the source directory. The other commands are incorrect for various reasons:

A. tar --new work.tar ./work/ is incorrect because there is no --new option in the tar command. The correct option for creating a new archive is --create or -c.

C. tar –create work.tgz –content ./work/ is incorrect because the -content option is not valid. The correct option for specifying the source files or directories is --files-from or -T. Also, the work.tgz file name implies compression, but the command does not use any compression option such as -z, -j, or -J.

D. tar work.tar < ./work/ is incorrect because the tar command does not accept input redirection from the standard input. The correct way to use the tar command is to provide the options and arguments after the command name.

E. tar work > work.tar is incorrect because the tar command does not produce output redirection to the standard output. The correct way to use the tar command is to use the -f option to specify the output file name. References: : tar command in Linux with examples - GeeksforGeeks : tar Command in Linux With Examples | phoenixNAP KB

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