Tutorial 1: Using Your Matrix Server Account

USING YOUR MATRIX SERVER ACCOUNT

Main Objectives of this Practice Tutorial

• Learn how to access your Matrix server account (from home and/or from Seneca computer lab).

• Learn several ways to exit your Matrix Linux Account session.

• Understand the Linux command structure and how to get help with Linux command usage.

• Become efficient with Linux command line editing by using short-cut keys.

• Issue a checking program (i.e. Shell Script) to confirm that you accessed your Matrix account.

• Perform LINUX PRACTICE QUESTIONS for additional practice
  
  

Tutorial Reference Material

Course Notes / Software		Linux Command/Shortcut Reference		YouTube Videos
Slides: Week 1 Lecture 1 Notes: PDF | PPTX Week 1 Lecture 2 Notes: PDF | PPTX Tutorials: HOWTO: Access Your Matrix Account Les Czegel's Week 1 Notes (HTML) Windows SSH client Software: SSH/SFTP Putty Bitvise SSH Client MovaXterm		Matrix Account Access: logout , exit <ctrl><d> passwd Command Line Editing: Bash Shell Shortcut Keys	General Linux Commands: pwd cd ls cal date who , w whoami ,who am i clear , <ctrl><l>	Brauer Instructional Videos: Connecting to Matrix Using SSH Client, and Running UBUNTU Within Windows 10 Linux File System, Basic Navigation (ls, cd, pwd, tree), Absolute and Relative Paths

KEY CONCEPTS

Purpose of Having a Matrix Linux Server Account

While attending Seneca College, you will be using many different computer systems. Some of these servers include:

my.senecacollege.ca	Learning Content Management System (Link to Resources / Student Grades / Online Quizzes)
ict.senecacollege.ca	Online access to slides, documents via webpage links
wiki.cdot.senecacollege.ca	Student Notes / Tutorials (weekly, review) / Practice Questions / Resources
matrix.senecacollege.ca	Linux Account for "hands-on Practice"

A shell is an interface / interpreter to allow a user to communicate with the Linux computer system.

Although you need to study concepts throughout this course (slides, etc.), you will also need to get hands-on practice running Linux commands as well as performing and submitting online tutorials.
This requires that you connect to a Linux server and become comfortable with issuing Linux commands.

In Unix/Linux, a shell is simply an interface to allow a user to communicate with the Linux computer system (server). Linux shells have evolved (improved) over a period of time. You will be using the Bash Shell which is considered to be user-friendly. By understanding how to issue Linux commands, you can create a file that contains Linux commands (called a shell script) later in this course to automate tasks to make you a more productive Linux user and system administrator.

Layout of the Matrix Linux Server

The Matrix server consists of several Computers connected together to form a cluster. A Linux Cluster is a cost effective alternative to larger servers.

The Matrix server consists of several computers connected together to form a cluster.
A Linux cluster is a cost effective alternative to buying larger servers.

All registered students in this course should have an account on the Matrix server.
You will be using this account for the following reasons:

• Issuing Linux commands
• Becoming productive using the Linux command prompt (shell)
• Performing Linux Tutorials (11)
• Performing Linux Practice Questions
• Performing Review Tutorial Questions (2)

Connecting to the Seneca Student VPN

Seneca Student VPN

Seneca College is "rolling-out" additional measures to improve network security. One of these measures is to implement multi-factored authentication. As of September 2020, all Seneca College students are required to connect to the Seneca Student VPN in order to be able to connect to their Matrix Linux account.

Multi-factor authentication is an electronic authentication method in which a computer user is granted access to a website or application only after successfully presenting two or more pieces of evidence (or factors) to an authentication mechanism: knowledge (something the user and only the user knows). Reference: https://en.wikipedia.org/wiki/Multi-factor_authentication

You should have received an email message (also available in course announcements) regarding how to setup your Smart Phone to connect and valid via the Seneca Student VPN. NOTE: If you haven't done this yet, please perform the steps provided in the following link:
https://students.senecacollege.ca/spaces/186/it-services/wiki/view/1025/student-vpn

In the next investigation, you will learn how to connect to and login to your Matrix server account from a remote computer
such as your home desktop computer, laptop or tablet computer.

Connecting to Your Matrix Account

There are two basic methods to connecting to your Matrix account:

Connect to Matrix viassh command

Method 1: Run ssh Command from command prompt:

After connecting to the Seneca Student VPN, you can open a command terminal
in your Newer Windows 10, Mac or Linux computer and issue the following command:

ssh senecauserid@matrix.senecacollege.ca

Connect to Matrix via graphical SSH Program

Method 2: Run graphical ssh program via MyApps in Seneca computer lab:

If you are in a Seneca computer lab, you can use MyApps to run a graphical SSH application for your Windows machine. One advantage of using this method is that you are already at Seneca and are NOT required to connect to the student VPN.

NOTE: You instructor may show you how to run a graphic Linux VM in order to connect to your Matrix account (if interested, refer to the optional tutorial at the end of this semester).

INVESTIGATION 1: ACCESSING YOUR MATRIX LINUX ACCOUNT

ATTENTION: Effective May 9, 2022 - this online tutorial will be required to be completed by
Friday in week 2 by midnight to obtain a grade of 2% towards this course

In this section, you will learn how to access your Matrix Linux account by two different methods:

• From your home computer
  
• From a workstation in a Seneca College lab via MyApps

METHOD 1: CONNECTING TO YOUR MATRIX ACCOUNT FROM YOUR HOME COMPUTER

The Seneca Student VPN service must be connected.

You will now learn a quick and simple method of connecting to your Matrix account by opening
a text-based terminal (in any OS) and issuing the ssh command.

Perform the Following Steps:

1. If you want to connect to your Matrix account from home, you MUST first connect to the Seneca Student VPN.
   Make certain that your Seneca Student VPN is connected.
   
   NOTE: If you haven't set this up, refer to the following link for instructions;
   https://students.senecacollege.ca/spaces/186/it-services/wiki/view/1025/student-vpn
   
   You only have to connect to your Seneca student VPN once during the day,
   or while you are logged into your computer.
   
   
2. Determine which operating system that your computer is using.
   
   
3. Try connecting to your Matrix account using the instructions in the table below based on your current operating system.
   
   

Newer Version of Windows 10:	MacOSX:	Linux:
From the start menu, type cmd and launch program In the command terminal, enter the following command: ssh senecausername@matrix.senecacollege.ca	Click Launchpad icon, type terminal and press ENTER In the terminal, enter the following command: ssh senecausername@matrix.senecacollege.ca	From the menu, choose: Applications > System Tools > Terminal In the terminal, enter the following command: ssh senecausername@matrix.senecacollege.ca

4. When connecting securely for the first time, a dialog box will appear to share a "public key" with your Matrix account in order to make your interaction between your workstation and the remote Linux server secure within the network (i.e. encrypted to prevent unauthorized access by other users)
   
   FYI: To make communications over a network secure, a computer generates two keys: a private key that is kept on the computer, and a public key, which can be shared with other computers. Transmissions from your computer uses the private key to encrypt (scramble) transmission to the remote computer, which in turn, uses the public key to decrypt (unscramble) the transmission. Likewise, the remote computer uses the public key to encrypt (scramble) transmissions and your computer uses the private key to decrypt (unscramble) those transmissions.
   
   
5. Type yes and press ENTER to share your public key.
   
   Next, a dialog box will appear prompting you for your Matrix account password in order to gain entry to your Matrix account.
   Your Matrix password is identical to your Seneca password.
   
   NOTE: As you type the password, the text may be hidden to prevent others from viewing your password
   
   
6. Enter your Seneca password and press ENTER
   
   
NOTE: If you encounter an error message, this can occur for several reasons:
1. You mis-spelled the name of the server
2. You mis-spelled your Matrix username (same username that you connect to my.senecacollege.ca)
3. You have CAPS LOCK on by mistake (your username should be lowercase only).
4. You mis-spelled your password (same password that you connect to my.senecacollege.ca)
   
   If you continue to experience the same problems, click on the following link for IT service desk contact info:
   IT service desk.
   
   
7. If you entered your password correctly, the Matrix Linux shell should appear where you can enter Linux commands.
   
   The Matrix server has been configured to allow users to only interact with the Linux OS by issuing commands.
   The main reason for this is to force students to learn how to issue Linux commands.
   
   
8. To exit your Matrix session, type the command exit followed by ENTER
   
   NOTE: You should notice that you are returned to the original command prompt where you issued the ssh command.
   
   
9. Type the same command at the command terminal prompt: exit followed by ENTER
   
   NOTE: You should notice that the you are disconnected and that the original terminal window has automatically closed.
   
   
10. Try accessing your Matrix account, and then exiting your Matrix account several times to become familiar with this process.
    
    You will now learn an alternative method to access your Matrix account (if you have an MS Windows machine)
    by downloading and running a graphical SSH application.

METHOD 2: CONNECTING TO YOUR MATRIX ACCOUNT FROM SENECA COMPUTER LAB

NOTE: This section requires you have access to a Seneca computer lab on campus.
If you don't have access to a Seneca computer lab this semester, then you can skip this section

You can also connect to your Matrix server account in the Seneca Computer lab via MyApps.

One advantage of this method is that your are at the college; therefore, you do NOT have to worry about connecting to the Seneca VPN. Another advantage of using this method is to introduce you to a graphical program to allow you connect to your Matrix account as opposed to using the ssh command (shown in the previous section).

MyApps (AppsAnywhere) Main Window

This method would also be useful if you do not have a home (notebook) computer and have access to a Seneca computer lab workstation.

MyApps (AppsAnywhere) is an application streaming service that lets you install software on any Seneca PC on demand. Any software application on the MyApps menu can be used on computers in classrooms, labs, and the Computing Commons.

Reference: https://inside.senecacollege.ca/its/software/myapps/

You will now use MyApps on your Windows workstation in your Seneca lab room to launch an application
to allow you to connect and login to your Matrix server account.

Several SSH applications will appear. We will use the application called SSH Client for this practice tutorial.

Perform the Following Steps:

1. Start your workstation in your lab and login to your Seneca Windows account.
   
   
2. Make certain that the MyApps window is open. This window should have opened shortly after you logged into your Windows workstation. If the application windows is not open, click on the MyApps icon on the desktop to launch).
   
   
   

   SSH Client Application Window
   NOTE: You may be required to validate in order to use MyApps correctly. If you see near the top of the screen "requires validation", then click on that area to connect to validate.
   
   
3. Click on the Search Apps area located in the top right corner of the MyApps window and type the word: ssh
   
   
4. Several SSH applications will appear.
   
   NOTE: All of these applications allow you to connect to your Matrix account.
   We will use the application called SSH Secure Shell Client for this practice tutorial.
   
   
5. Launch the SSH Secure Shell Client application icon to launch this program.
   
   
   

   Quick Connect Dialog Box
   NOTE: Prior to launching the application, you can add this to your favourites which will make it faster
   to access this application in the future.
   
   
6. The main SSH Client window will appear. Click on the Quick Connect button.
   
   NOTE: The Connect dialog box allows the user to specify the server name and your account name
   to allow you to connect to the server.
   
   
7. Click on the textbox labelled Hostnanme and enter the text: matrix
   
   NOTE: You can use the hostname matrix since you are located inside Seneca's network.
   If you where located outside Seneca's network, then you would need to enter the full domain name: matrix.senecac.on.ca
   
   
   

   Dialog Box to Share Public Key on Remote Server
8. When connecting securely for the first time, a dialog box will appear to share a "public key" with your Matrix account in order to make your interaction between your workstation and the remote Linux server secure within the network (i.e. encrypted to prevent unauthorized access by other users)
   
   FYI: To make communications over a network secure, a computer generates two keys: a private key that is kept on the computer, and a public key, which can be shared with other computers. Transmissions from your computer uses the private key to encrypt (scramble) transmission to the remote computer, which in turn, uses the public key to decrypt (unscramble) the transmission. Likewise, the remote computer uses the public key to encrypt (scramble) transmissions and your computer uses the private key to decrypt (unscramble) those transmissions.
   
   
   

   Password Dialog Box
9. Click the Yes button to share your public key.
   
   
10. Next, a dialog box will appear prompting you for your Matrix account password in order to gain entry to your Matrix account. Your Matrix password is identical to your Seneca password. As you type the password, the text will be blocked-out or hidden to prevent others from viewing the screen to obtain your password
    

    Authentication Response Dialog Box
    
    
    
11. Enter your password and click OK or press ENTER
    
    
    

    SSH Login Error
12. Click OK or press ENTER at the Authentication Response dialog box.
    
    NOTE: If you encounter an error message, this can occur for several reasons:
    1. You mis-spelled the name of the server
    2. You mis-spelled your Matrix username (same username that you connect to my.senecacollege.ca)
    3. You have CAPS LOCK on by mistake (your username should be lowercase only).
    4. You mis-spelled your password (same password that you connect to my.senecacollege.ca)
    
    If you continue to experience the same problems, click on the following link for IT service desk contact info:
    IT service desk.
    
    
    

    Matrix Shell Command Line Interface
13. If you entered your password correctly, the main SSH Linux shell should appear where you enter Linux commands.
    
    The Matrix server has been configured to allow users to only interact with the Linux OS by issuing commands. There are various reasons for this, but the main 2 reasons are to force students to learn how to issue Linux commands as well as limitations to remote access to a graphical Linux server due to large number of users (students).
    
    
    

    SSH Settings Dialog Box

You can configure the SSH application to adjust elements such as the window size and text font type and text font size. We will be showing you how to configure your SSH Secure Shell Client, but the other applications can allow you to configure their settings.

Perform the Following Steps:

1. Click on the Edit menu item, and then select Settings in the Edit drop-down menu.
   
   
2. To change the size of your shell window, under the Global Settings section, click Appearance
   
   
3. Change the window size both horizontal and vertical to larger values.
   
   
4. To change the font size, under the Global Settings section, click Font
   
   
5. Select a larger font size and click OK
   
   
6. You now should notice that you have customized your SSH shell terminal. You can use the settings screen to also change your background and text colours if you are interested in doing so.
   
   
7. To exit your Matrix session, type the following command and press ENTER: exit
   
   NOTE: You should notice that the colour of the text changes slightly when disconnected and you are unable to issue Linux commands from that window.
   
   
8. After you have disconnected from your account, close the SSH Secure Shell Client application window.
   
   
9. It is recommended to repeat these steps with connecting to your Matrix account from a Seneca lab workstation until you become comfortable with the process.
   
   

In the next investigation, you will learn how to issue Linux commands from the command prompt (referred to as the "shell"), learn how to get help with Linux commands, use command-line editing short cut keys, and run a program to confirm that you connected to your Matrix account in order to get marks for this online tutorial.

INVESTIGATION 2: USING THE LINUX SHELL

In this investigation, you will learn how to use the Linux Shell. Topics in the section include:

• Learn the basic Linux command structure (arguments and options)
• Learn how to get help for Linux commands via the online manual (i.e. man command).
• Perform Basic Shell Editing
• Issue a program to confirm that you connected to your Matrix account
  
  

The Bash shell in Matrix allows you to interact with your Matrix account by issuing commands.

The General Linux Command Structure is as follows:
command argument1 argument2 ...

Some Linux commands can be issued by entering the Linux command line without arguments (e.g. pwd, date, ls, cal),
but many Linux commands can be issued with arguments (e.g. cal 2002, cd /bin, ls -l -a /bin ).

What Does an Argument Represent?

An argument can respresent:

• a file pathname
• a command option
• a series of characters (i.e. text) that the command can use

An argument is separated from a command (or from other arguments) by a SPACE, MULTIPLE SPACES or a TAB.

Perform the Following Steps:

1. Make certain that you are logged into your Matrix account.
   
   
2. Issue the following Linux command: pwd
   
   The output from this Linux command basically shows your current location in the Matrix server.
   This represents a directory pathname to your home directory. We will discuss pathnames later in this course.
   
   
3. Issue the following Linux command: ls
   
   What do you notice?
   
   If there were any files in your home directory, just their file names would be displayed.
   
   
4. Issue the following Linux command: cd /bin
   
   
5. Issue the following Linux command to confirm your current location: pwd
   
   
6. Issue the following Linux command: ls
   
   What do you notice?
   
   
7. Issue the following Linux command using an option: ls -l
   
   What do you notice?
   
   The -l option with the ls command provides a detailed ("long") listing of files providing more information on a separate line for each file.
   
   
8. Issue the following Linux command to return to your home directory: cd
   
   
9. Issue the following Linux command to confirm your current location: pwd
   
   
10. Issue the following Linux command: ls /bin
    
    
11. Issue the following Linux command to confirm your current location: pwd
    
    What do you notice?
    
    What makes this command with that argument useful if you are current located in your home directory?
    
    
12. Issue a Linux command that you have already learned to change to your home directory
    and to confirm that you have returned to your home directory.
    
    
13. Issue the following Linux command: clear
    
    What do you notice? How would this command be helpful?
    FYI: The short-cut keys to clear the screen for the Bash shell is: ctrl-l
    
    
14. Issue the following Linux command: who
    
    What information does this command show?
    
    This command lists users that are logged into the same Matrix server as yourself.
    NOTE: Remember that the Matrix Linux cluster contains several servers, so it does not display
    all users that are logged onto those other machines within that cluster!
    
    
15. Issue the following Linux command: whoami
    
    What does this command display? What do you think is the purpose of this command?
    
    
16. Issue the following Linux command: cal
    
    What is the purpose of this command?
    
    
17. Issue the following Linux command: cal 2021
    
    What is the purpose of this command using this argument?
    
    
18. Issue the following Linux command: cal 2 2021
    
    What is the purpose of this command using those two numbers as arguments?
    
    

Getting Help with Linux Commands

With the Linux OS containing over 2500 commands and utilities, it is good for a Linux user or
Linux system administrator (sysadmin) to learn about how to use commands “on-the-fly”.

The man command can provide information on how to use a command
(i.e. command usage, acceptable command arguments, command options, examples).

1. Issue the following command: man man
   
   You may notice that the online manual categories commands into sections or numbered volumes.
   
   
2. Type the SPACE key to move to the next screen.
   
   How many volume numbers are contained in the man pages (like executable commands,
   games, or system administrator commands)?
   
   TIP: You can use the following short-cut keys within the man command to
   help navigate throughout this utility to get help with the ls command (refer to table below):
   
   

   Keyboard Shortcut	Purpose
   ENTER	Move down one line
   SPACEBAR	Move one screen down
   <ctrl><b>	Move one screen up
   /pattern/	Search for Pattern
   q	quit man utility

   
   
3. Press the letter q to exit the man command.
   
   
4. Issue the following Linux command to get help with the ls command: man ls
   
   
5. Navigate through the man utility for the ls Linux command and note the option letters that correspond to the following descriptions:
   
   • "use a long lising format"
   • "do not ignore entries starting with ." (i.e. hidden files)
   • "sort by file size"
   • "append indicator (one of */=>&|) to entries" (i.e. type of file)
   
   
6. Exit the man utility for the ls command.
   
   
7. Issue the ls command for each of those option letters you noted in step 4 to see how this command differs for each option.
   
   NOTE: The man utility can be used with the -k option to help list Linux commands that match a text pattern
   that is contained within the help screen for a Linux command.
   
   
8. Pipeline commands can be used to filter-out unnecessary output. In the next command that you will be issuing,
   the output from the man -k command, is sent into the grep command to filter (i.e. trap) only output that matches the pattern "8"
   (The number "8" refers to the category of type of command - in this case, administration commands).
   
   We will learn more about pipeline commands later in this course.
   
   
9. Issue the following Linux pipeline command: man -k user | grep 8
   
   How does this pipeline command make it easier to obtain information regarding man command?
   
   
10. If you wish to change your password, you can change it by issuing the command: passwd
    What option for the passwd command can be used to change user info (such as name)?
    Hint: use the man command for passwd.
    
    
11. Press the letter q to exit the man command.
    
    NOTE: Do NOT run the passwd command. Unique for this college, your Matrix password
    is changed automatically when you change your myseneca password.
    
    You will now learn how to perform command line editing
    to correct syntax errors while typing Linux commands PRIOR to pressing the ENTER key.
    
    

Command Line Editing

Command Line Editing Shortcut Keys.

Learning shortcut keys in any OS terminal will allow you to be more productive as a Linux user or Linux System Administrator (commonly referred to as: Linux sysadmin).


Let's learn a few common Bash Shell keyboard shortcut keys and find out where you can access online help for additional shortcuts (if required).

Perform the Following Steps:

To make alt-f key work, select Edit -> Settings -> Keyboard, and select the checkbox Use ALT as Meta key (and Escape).

1. Type the following Linux command, but DON’T press the ENTER key:
   cd /bin
   
   
2. Press the ctrl-a key combination. What happens?
   
   NOTE: To make alt-f key work when use the GRAPHICAL Windows SSH Client application, select Edit -> Settings -> Keyboard, and select the checkbox Use ALT as Meta key (and Escape).
   
   
3. Press the alt-f key combination two times
   (OPTION+right-arrow for Mac OSx).
   
   
4. Press the alt-b key combination one time.
   (OPTION+left-arrow for Mac OSx).
   
   

   alt-b moves one word backwards for Windows OS

   ctrl-w deletes a word to left of the cursor.

   After command is deleted, then type new command and press ctrl-e to move to end of the command line.

5. Press the ctrl-w shortcut key. What happens?
   
   
6. Type the following command: ls
   
   
7. Press the ctrl-e key combination
   
   What happens?
   
   
8. Press the ENTER key to execute the command.
   
   
9. Press the up arrow key. What happens?
   
   
10. Press the ctrl-u key combination. What happens?
    
    
11. Press the up arrow key combination, and see what happens when you press BACKSPACE , <ctrl><BACKSPACE> and <ctrl><h>.
    Why is it important to know those series of key combinations?
    
    
12. Press the ctrl-u key combination to clear the line.
    
    
13. Press the ctrl-l key combination. What happens? What is the advantage of using ctrl-u as opposed to ctrl-l?
    
    The Bash shortcut keys that you just learned are sufficient to perform Bash Shell editing.
    Although you are NOT required to learn other short-cut keys, here is a link to a listing in case you are interested:
    [https:// ostechnix.com/list-useful-bash-keyboard-shortcuts/ Useful Bash Shell Keyboard Shortcuts]
    
    

Running a Shell Script to Check Student Online Tutorial Participation

Some professors will require students successfully perform these online tutorials for marks (within a deadline).
In order to confirm that you successfully performed a tutorial, you will be required to run a program
(or in later tutorials, several programs) to prove that you successfully completed tasks in a tutorial.

These programs (known as Shell Scripts) will check your work and offer feedback if you made mistakes, so you can make corrections.
Making corrections (i.e. troubleshooting) and re-running these checking programs until you are successful will help students
gain "hands-on" experience as well as "trouble-shooting experience.

Students whose professors do NOT assign marks for these online tutorials are encouraged to perform them for "hands-on" practice. The checking program for this tutorial is just showing proof that you were able to connect to your Matrix account from your home computer.

If all all check pass, then user performed can proceed.

If there is a warning, then feedback is provided to user to correct and re-run checking script.

If you have correctly completed the required tasks, the user can proceed. If the checking shell script detects an error, then it will provide feedback to allow the student to fix that problem so they can re-run the checking shell scripts until they have successfully completed a task.

Perform the Following Steps:

1. Make certain that your current directory is your home directory
   By entering the following Linux command:
   cd
   
   
2. Issue the following command to run a checking script :
   ~uli101/week1-check
   
   The beginning character "~" is called tilde. You get this character by pressing SHIFT + `
   (which is the key to the left of the number 1 on your keyboard).
   
   
3. Your screen should clear and indicate that you have proved that you have successfully logged in.
   
   
4. An email will be sent to your Seneca email as confirmation in case your ULI101 professor is assigning marks to these tutorials.
   
   Keep those confirmation email messages for the duration of this semester as proof that you have completed those checking scripts in case there is a discrepancy in tutorial grades.
   
   

LINUX PRACTICE QUESTIONS

The purpose of this section is to obtain extra practice to help with quizzes, your midterm, and your final exam.

Here is a link to the MS Word Document of ALL of the questions displayed below but with extra room to answer on the document to simulate a quiz:

https://ict.senecacollege.ca/~murray.saul/uli101/uli101_week1_practice.docx

Your instructor may take-up these questions during class. It is up to the student to attend classes in order to obtain the answers to the following questions. Your instructor will NOT provide these answers in any other form (eg. e-mail, etc).

Review Questions:

1. What is a “Linux Cluster”? What is an advantage of using a Linux cluster?
2. List three unique server names at Seneca college and briefly explain the purpose of that server.
3. List the steps to connect and login to your Matrix Seneca College account on your laptop or your home computer.
4. List alternative methods to connect to your Matrix account, including if you have an Apple Mac computer or are running the Linux operating system.
5. List 3 unique ways to log-out of your Matrix account (not including closing the SSH window or application).
6. What is the difference between a Linux command and an argument?
7. What is the purpose of a Linux command option?
8. What character(s) are used to separate commands and arguments?
9. Create a table listing each Linux command, useful options that were mentioned in this tutorial for the following Linux commands:
   pwd , cd , ls , cal , date , who , w , whoami , who am I , clear