IST Unit 1 review

What is a Linux distribution?

1. A Linux distribution is an installable operating system constructed from a Linux kernel and supporting user programs and libraries. A complete Linux operating system is not developed by a single organization, but by a collection of independent open-source development communities working with individual software components. A distribution provides an easy way for users to install and manage a working Linux system.

Explain what is meant by command line.

1. A command line is a text-based interface which can be used to input instructions to a computer system. The Linux command line is provided by a program called the shell. The command line is a blank line and cursor on the screen, allowing the user to type in instructions for immediate execution. Command line is a computer program intended to interpret commands.

Explain the difference between a hard link and a soft link, including the advantages and disadvantages of both.

1. A symbolic or soft link is an actual link to the original file, whereas a hard link is a mirror copy of the original file. If you delete the original file, the soft link has no value, because it points to a non-existent file. But in the case of hard link, it is entirely opposite. A soft link points to another entry somewhere in the file system. A soft link has the ability to link to directories, or to files on remote computers networked through NFS. Deleting a target file for a symbolic link makes that link useless. A hard link preserves the contents of the file. A hard link cannot be created for directories, and they cannot cross filesystem boundaries or span across partitions. In a hard link you can use any of the hard link names created to execute a program or script in the same manner as the original name given. A hard link points a name to data on a storage device. A soft link points a name to another name, that points to data on a storage device.

What is meant by a file system hierarchy?

1. All files on a Linux system are stored on file systems, which are organized into a single inverted tree of directories, known as a file-system hierarchy. This tree is inverted because the root of the tree is said to be at the top of the hierarchy, and the branches of directories and subdirectories stretch below the root. The / directory is the root directory at the top of the file-system hierarchy. The / character is also used as a directory separator in file names. For example, if etc is a subdirectory of the / directory, you could refer to that directory as /etc. Likewise, if the /etc directory contained a file named issue, you could refer to that file as /etc/issue. Subdirectories of / are used for standardized purposes to organize files by type and purpose. This makes it easier to find files.

Explain what an absolute path is. Define a relative path and compare it to an absolute path.

1. An absolute path is a fully qualified name, specifying the file's exact location in the file system hierarchy. It begins at the root (/) directory and specifies each subdirectory that must be traversed to reach the specific file. Every file in a file system has a unique absolute path name, recognized with a simple rule: A path name with a forward slash (/) as the first character is an absolute path name. For example, the absolute path name for the system message log file is /var/log/messages. Absolute path names can be long to type, so files may also be located relative to the current working directory for your shell prompt. A relative path identifies a unique file, specifying only the path necessary to reach the file from the working directory. Recognizing relative path names follows a simple rule: A path name with anything other than a forward slash as the first character is a relative path name. A user in the /var directory could refer to the message log file relatively as log/messages. An absolute path refers to the same location in a file system relative to the root directory, whereas a relative path points to a specific location in a file system relative to the current directory you are working on.

What does the option --help do? Explain.

1. An initial setup program runs to help them configure basic account settings. The help option is a command that help user when they first start using the program or when they need some guidance on a situation. The help is easily accessible and includes videos and documentation to help orient new users and current one to the GNOME 3 environment.

What is bash? What is sh? What is the difference between bash and sh?

1. Bash is the shell, or command language interpreter, for the GNU operating system. Bash (Bourne again shell) is a shell replacement for the Bourne shell. Bash is superset of sh. Bash supports sh. 2) Sh is a command language interpreter that executes commands read from a command line string, the standard input, or a specified file. Sh (Bourne shell) is a shell command-line interpreter, for Unix/Unix-like operating systems. It provides some built-in commands. 3) The difference between the two are bash shell provides a scripting language that can support automation of tasks and the shell has additional capabilities that can simplify or make possible operations that are hard to accomplish efficiently with graphical tools.

List and define the three parts of a Linux command

1. Command- The command is the name of the program to run. 2) Options- The options which adjust the behavior of the command or what it will do. 3) Arguments- The arguments which often indicate a target that the command should operate on.

What is Fedora?

1. Fedora is a community project that produces and releases a complete, free, Linux-based operating system. Red Hat sponsors the community and works with community representatives to integrate the latest upstream software into a fast-moving and secure distribution. The Fedora project contributes everything back to the free and open-source world, and anyone can participate. which makes it less suitable for enterprise use.

What is the RHEL8 tool used to view GNU info pages?

1. Info documentation is structured as hyperlinked info nodes Like man pages, info nodes are read from the command line, using either the info or pinfo commands [student@workstation ~]$ pinfo

List three ways Linux is used today in modern datacenters

1. Linux is open-source software 2) Linux provides easy access to a powerful and scriptable command-line interface 3) Linux is a modular operating system that allows you to easily replace or remove components.

What are GNU Info pages?

1. Man pages have a format useful as a command reference, but less useful as general documentation. For such documents, the GNU Project developed a different online documentation system, known as GNU Info. Info documents are an important resource on a Red Hat Enterprise Linux system because many fundamental components and utilities, such as the coreutils package and glibc standard libraries, are either developed by the GNU Project or utilize the Info document system. GNU Info was designed to offer documentation that was comprehensive, hyperlinked, and possible to output to multiple formats. GNU Info was designed to offer documentation that was comprehensive, hyperlinked, and possible to output to multiple formats. Man pages were available, and they were great at providing printed output. However, they were designed such that each man page had a reasonably small set of content. Info documents typically cover particular software packages as a whole, tend to have more practical examples of how to use the software, and are structured as hypertext documents.

What is the difference between man pages and GNU Info pages?

1. Man pages have a much more formal format, and typically document a specific command or function from a software package, and are structured as individual text files. Info documents typically cover particular software packages as a whole, tend to have more practical examples of how to use the software, and are structured as hypertext documents. Generally, man pages are more about 1 specific topic a command, a config file, a system function, while info normally has more the structure of a combined manual, more like a book.

In your own words define what metacharacters are.

1. Metacharacters are special characters that are used to represent something other than themselves. As a rule of thumb, characters that are neither letters nor numbers may be metacharacters. Meta-characters that "expand" to match file and path names being sought, commands perform on a focused set of files at once.

Describe three reasons you should learn about Linux

1. One good reason to learn about Linux, Linux is the best skill to have to get into IT they are a high demand. 2) The second good reason to learn about Linux, most mobile application devices are operating on the system. 3) The third good reason to learn about Linux, Windows users need to work in conjunction with Linux.

Explain in detail what open-source software is

1. Open- source is software with source code that anyone can use, study, modify, and share. 2) Open- source is the set of human-readable instructions that are used to make a program. 3)Open- source promotes collaboration, sharing, transparency, and rapid innovation because it encourages people beyond the original developers to make modifications and improvements to the software and to share it with others.4) Open-source vendors such as Red Hat provide commercial help with deploying, supporting, and extending solutions based on open-source products. 5) Open-source software is a software that can help you learn from real-world code and develop more effective applications.

(1) Who is Bruce Perens?

1. Perens is an American computer programmer and advocate in the free software movement. He created The Open-Source Definition. Perens currently works as an Open-Source evangelist for Hewlett-Packard. He is a partner at OSS Capital.

List three ways to "try out" Red Hat Enterprise Linux as detailed in Chapter 1.

1. Red Hat also makes available free subscriptions to several products for development purposes through the Red Hat Developer Program. 2) Another approach is to deploy an instance of Red Hat Enterprise Linux made available through a cloud provider. 3) Another way is to download an evaluation copy from the website.

In detail describe what Red Hat is.

1. Red Hat is the world's leading provider of open-source software solutions, using a community-powered approach to reliable and high-performance cloud, Linux, middleware, storage, and virtualization technologies. Red Hat's mission is to be the catalyst in communities of customers, contributors, and partners creating better technology the open-source way. Red Hat's role is to help customers connect with the open-source community and their partners to effectively use open-source software solutions. Red Hat actively participates in and supports the open-source community and many years of experience have convinced the company of the importance of open source to the future of the IT industry.

Explain the multistage process that Red Hat uses to integrate open-source software into RHEL?

1. Red Hat uses the multistage process to integrate open-source software into RHEL because it participates in supporting individual open-source projects. It contributes code, developer time, resources, and other support, often collaborating with developers from other Linux distributions. It helps to improve the general quality of software for everyone. Red Hat sponsors and integrates open-source projects into a community-driven Linux distribution. Red Hat stabilizes the software to ensure that it is ready for long term support and standardization.

Who is Richard Stallman?

1. Stallman founded the GNU Project in 1984 to create his own Unix-like operating system that was freely shareable. He also started the Free Software movement to espouse his political agenda of freely shared intellectual property. Stallman's philosophical and technical work became the foundation for Linux and the Open-Source movement.

What are man pages?

1. The historical Linux Programmer's Manual, from which man pages originate, was large enough to be multiple printed books. Man pages are online references manuals, each of which covers a specific Linux command. The man pages are read from the terminal and are all presented in the same layout. One source of documentation that is generally available on the local system are system manual pages or man pages These pages are shipped as part of the software packages for which they provide documentation and can be accessed from the command line by using the man command. The historical Linux Programmer's Manual, from which man pages originate, was large enough to be multiple printed sections. Each section contains information about a particular topic.

What is the difference between passwd(1) and passwd(5) in the passwd man pages?

1. To distinguish identical topic names in different sections, man page references include the section number in parentheses after the topic. For example, passwd(1) describes the command to change passwords, while passwd(5) explains the /etc/passwd file format for storing local user accounts. To read specific man pages, use man topic. Contents are displayed one screen at a time. The man command searches manual sections in alphanumeric order. For example, man passwd displays passwd(1) by default. To display the man page topic from a specific section, include the section number argument: man 5 passwd displays passwd(5). The difference between passwd(1) and passwd(5) in the passwd man pages is passwd(1) describes the command and passwd(5) explains the file format.

List the procedure to shut down a RHEL8 server from the GNOME3 desktop.

1. To shut down the system, select (User) → Power Off from the top bar or press Ctrl+Alt+Del. In the dialog that appears, the user can choose to Power Off, Restart the machine, or Cancel the operation. If the user does not make a choice in this dialog, the system will automatically shut down after 60 seconds.

List the nine different sections that can be found in man pages.

1. User commands(both executable and shell programs), System calls (kernel routines invoked from user space), Library functions (provided by program libraries), Special files (such as device files), File formats (for many configuration files and structures), Games (historical section for amusing programs), Conventions, standards, and miscellaneous (protocols, file systems), System administration and privileged commands (maintenance tasks), Linux kernel API (internal kernel calls)

What is CentOS?

CentOS is a community-driven Linux distribution derived from much of the open-source Red Hat Enterprise Linux codebase and other sources. It is free of charge, is easy to install, and is staffed and supported by an active user community of volunteers that operates independently of Red Hat.

Who is Linus Torvalds?

In 1991 Torvalds created the Linux kernel (the unifying program for a Unix-like operating system) at age twenty-one while enrolled at the University of Helsinki in his native Finland. Torvalds is interviewed on his development of the Linux kernel as well as on the GNU/Linux naming controversy and Linux's further evolution, including its commercialization.

According to Chapter 1, who develops open source software?

Open-source development today is overwhelmingly professional. Many developers are paid by their organizations to work with open-source projects to construct and contribute the enhancements they and their customers need. Volunteers and the academic community play a significant role and can make vital contributions, especially in new technology areas. The combination of formal and informal development provides a highly dynamic and productive environment.

What is Red Hat Enterprise Linux?

Red Hat Enterprise Linux (RHEL) is Red Hat's enterprise-ready, commercially supported Linux distribution. It is the leading platform for open-source computing, not just a collection of mature open-source projects. RHEL is extensively tested, with a large supporting ecosystem of partners, hardware and software certifications, consulting services, training, and multiyear support and maintenance guarantees. Red Hat Enterprise Linux uses a subscription-based distribution model. Because this is open-source software, this is not a license fee. Instead, it pays for support, maintenance, updates, security patches, access to the Knowledgebase on the Red Hat Customer Portal (http://access.redhat.com/), certifications, and so on. The customer is paying for long-term support and expertise, commitment, and assistance when they need it.

Explain what a desktop environment is; give examples.

The desktop environment is the graphical user interface on a Linux system. The desktop environment is a collection of applications designed to work well with each other and provide a consistent user experience. 2) Some examples are GNOME 3, GNOME Shell and Red Hat Enterprise Linux 8.

In Chapter 1 you learned about the Linux CLI. Why is the CLI important in Linux?

The reason CLI is important is because the task can perform all administration task and it enables easier automation, deployment, and provisioning, and simplifies both local and remote system administration. Unlike other operating systems, these capabilities have been built in from the beginning

Define these Linux meta-characters as they apply to file globbing:

a. * = Any string of zero or more characters. b. ? = Any single character. c. [[:alpha:]] = Any alphabetic character d. [[:digit:]] = Any single digit from 0 to 9. e. [[:space:]] = Any single white space character. This may include tabs, newlines, carriage returns, form feeds, or spaces. f. [^aeiou] = Any character that is not listed in the square brackets. g. [aeiou] = Any character that is listed in the square brackets.

1. What is the purpose of the following Linux directories?

a. /boot - /boot Files needed in order to start the boot process. b. /etc - /etc Configuration files specific to this system. c. /root - /root Home directory for the administrative superuser, root. d. /usr - /usr Installed software, shared libraries, include files, and read-only program data. Important subdirectories include: /usr/bin: User commands. /usr/sbin: System administration commands. /usr/local: Locally customized software. /var - /varVariable data specific to this system that should persist between boots. Files that dynamically change, such as databases, cache directories, log files, printer-spooled documents, and website content may be found under /var.

Define what the following features of the RHEL8 GNOME3 desktop provide:

a. Activities Overview - This is a special mode that helps a user organize windows and start applications. The Activities overview can be entered by clicking the Activities button at the upper-left corner of the top bar, or by pressing the Super key. The Super key (sometimes called the Windows key or Command key) is found near the lower left corner of an IBM PC 104/105-key or Apple keyboard. The three main areas of the Activities overview are the dash on the left side of the screen, the windows overview in the center of the screen, and the workspace selector on the right side of the screen. b. dash- This is a configurable list of icons of the user's favorite applications, applications which are currently running, and a grid button at the bottom of the dash which can be used to select arbitrary applications. Applications can be started by clicking on one of the icons or by using the grid button to find a less commonly used application. The dash is also sometimes called the dock. c. message tray- The message tray provides a way to review notifications sent by applications or system components to GNOME. If a notification occurs, normally the notification first appears briefly as a single line at the top of the screen, and a persistent indicator appears in the middle of the top bar next to the clock to inform the user of notifications have been recently received. The message tray can be opened to review these notifications by clicking the clock on the top bar or by pressing Super+M. The message tray can be closed by clicking the clock on the top bar, or by pressing Esc or Super+M again. d. top bar- The bar that runs along the top of the screen. It is displayed in the Activities overview and in workspaces. The top bar provides the Activities button, and controls for volume, networking, calendar access, and switching between keyboard input methods (if more than one is configured). e. windows list- An area to the right of the Activities overview which displays thumbnails of all active workspaces and allows workspaces to be selected and windows to be moved from one workspace to another. f. Workspaces- Workspaces are separate desktop screens that have different application windows. These can be used to organize the working environment by grouping open application windows by task. For example, windows being used to perform a particular system maintenance activity (such as setting up a new remote server) can be grouped in one workspace, while email and other communication applications can be grouped in another workspace.

1. What do the following Linux commands do?

a. Cd - the cd command to change your shell's current working directory. If you do not specify any arguments to the command, it will change to your home directory. b. Ls - The ls command lists directory contents for the specified directory or, if no directory is given, for the current working directory. The ls command has multiple options for displaying attributes on files. The most common and useful are -l (long listing format), -a (all files, including hidden files), and -R (recursive, to include the contents of all subdirectories). c. Pwd - The pwd command displays the full path name of the current working directory for that shell. This can help you determine the syntax to reach files using relative path names. d. Touch - The touch command normally updates a file's timestamp to the current date and time without otherwise modifying it. This is useful for creating empty files, which can be used for practice, because "touching" a file name that does not exist causes the file to be created.

1. When navigating man pages, what key do you press to do the following:

a. Scroll backward (up) one screen - PageUp-Scroll backward (up) one screen b. Go to start of the man page. G-Go to start of the man page. c. Scroll forward (down) one screen Spacebar-Scroll forward (down) one screen PageDown -Scroll forward (down) one screen d. Exit man and return to the command shell prompt- Q- Exit man and return to the command shell prompt

Write a brief explanation of each of the following:

a. Tilde (~) expansion = The tilde character (~), matches the current user's home directory. If it starts a string of characters other than a slash (/), the shell will interpret the string up to that slash as a username, if one matches, and replace the string with the absolute path to that user's home directory. If no username matches, then an actual tilde followed by the string of characters will be used instead. b. Brace ({ }) expansion = Brace expansion is used to generate discretionary strings of characters. Braces contain a comma-separated list of strings, or a sequence expression. The result includes the text preceding or following the brace definition. Brace expansions may be nested, one inside another. Also double-dot syntax (..) expands to a sequence such that {m..p} will expand to m n o p. c. Command substitution ( $(command) ) = Command substitution allows the output of a command to replace the command itself on the command line. Command substitution occurs when a command is enclosed in parentheses, and preceded by a dollar sign ($). The $(command) form can nest multiple command expansions inside each other.

command

a. echo "Today is $(date +%A)." - echo "Today is $(date +%A)." = words enclosed in parenthesis with the $(date +%A) replaced with the day of the week. b. ls *.?? = list all the files in the current directory that has a two-character extension. c. ls -l [xyz]* = display a long list of file and directories that begin with any of the characters in the square brackets. d. ls -la *z* = display a list all files & directories including hidden ones that have a z anywhere in the name. e. touch volume{1..2}_chapter{1..6}.txt = create twelve empty txt files, where a one or a two is added after volume and a number one, two, three, four, five, or six is added after chapter.

Define these terms:

a. physical console - The hardware keyboard and display. b. Shell - The Linux command line is provided by a program. c. Terminal - Provides a keyboard for user input and a display for output. d. virtual console - Another way to access a shell and a Linux machine's physical console supports multiple virtual consoles which act like separate terminals.