|
|
| (113 intermediate revisions by the same user not shown) |
| Line 1: |
Line 1: |
| − | [[Category:OPS235]]
| + | #REDIRECT [[OPS235]] |
| − | | |
| − | | |
| − | = LAB PREPARATION =
| |
| − | [[Image:vmware-1.png|thumb|right|300px|At the end of lab2, your VMware Workstation application will contain '''4 virtual machines'''. You will now have the option to run one virtual machine at a time, or run all machines simultaneously to learn about networking (covered in later labs) ]]
| |
| − | | |
| − | === Purpose / Objectives of Lab2===
| |
| − | | |
| − | '''In this lab, you will create another three virtual machines''' to learn how to install Centos Linux in different ways including network installs.
| |
| − | <br><br>
| |
| − | <u>Main Objectives</u>
| |
| − | | |
| − | * '''Installing Virtualization Software''' on your '''c7host''' machine
| |
| − | * '''Create 3 separate VMs (virtual machines) using different installation methods:'''
| |
| − | :* Centos Live DVD (with Install to Harddisk program)
| |
| − | :* Network Centos Installation without configuration file
| |
| − | :* Network Centos Installation with configuration file (Kickstart)
| |
| − | * Understand the '''advantages and disadvantages of each type of installation''', and be able to '''select the best installation method''' for a particular situation.
| |
| − | * '''Manipulate virtual machines by CLI''' (virsh)
| |
| − | * '''Properly backup VMs and VM configuration''' in virtual manager application onto home directory and to external source (USB Key)
| |
| − | | |
| − | * Create and run '''Bash Shell scripts''' to automatically create a post-install report for an installed VM.
| |
| − | | |
| − | | |
| − | {|width="70%" cellspacing="0"
| |
| − | | |
| − | |- valign="top"
| |
| − | | |
| − | |colspan="2" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;"|Minimum Required Materials<br>
| |
| − | | |
| − | |colspan="3" style="font-size:16px;font-weight:bold;border-bottom: thin solid black;border-spacing:0px;"|Linux Command Reference<br>
| |
| − | |- valign="top"
| |
| − | | |
| − | | |[[Image:ubs-key.png|thumb|left|85px|<b>USB key</b><br>(for backups)]]
| |
| − | | |
| − | | |[[Image:log-book.png|thumb|left|70px|<b>Lab2 Log Book</b>]]
| |
| − | | |
| − | | valign="top"|
| |
| − | Virtualization<br>
| |
| − | [http://linux.die.net/man/1/virt-manager virt-manager]<br>
| |
| − | [http://linux.die.net/man/1/virsh virsh]<br>
| |
| − | Installation Guides<br>
| |
| − | [http://wiki.centos.org/HowTos/KVM Installing & Using KVM on CentOS ]<br>
| |
| − | [http://www.dedoimedo.com/computers/kvm-intro.html Using KVM (tutorial)]<br>
| |
| − | [https://www.centos.org/docs/5/html/5.2/Virtualization/sect-Virtualization-Commands_for_Red_Hat_Virtualization-virsh_the_command_line_interface_tool_for_virtualization.html virsh command reference ]<br>
| |
| − | |valign="top"|
| |
| − | Miscellaneous<br>
| |
| − | [http://unixhelp.ed.ac.uk/CGI/man-cgi?gzip gzip, gunzip]<br>
| |
| − | [http://unixhelp.ed.ac.uk/CGI/man-cgi?grep grep]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/wc.1.html wc]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/pwd.1.html pwd]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/ls.1.html ls]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/more.1.html more]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/file.1.html file]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/wget.1.html wget]<br>
| |
| − | [http://man7.org/linux/man-pages/man1/chmod.1.html chmod]<br>
| |
| − | [http://ss64.com/vi.html vi]
| |
| − | |valign="top"|Matrix Online Tutorials:<br><ul><li>Shell Scripting - Part 2 (Logic & Math Expressions):<br>'''/home/murray.saul/scripting-2'''</li><li>Shell Scripting - Part 3 (Loops)<br>'''/home/murray.saul/scripting-3'''</li></ul>
| |
| − | | |
| − | |}
| |
| − | | |
| − | =INVESTIGATION 1: USING VIRTUALIZATION SOFTWARE TO CREATE VIRTUAL MACHINES=
| |
| − | | |
| − | ===Part 1: Virtualization Application Setup / Comparison Chart===
| |
| − | | |
| − | [[Image:lab2-logbook.png|thumb|right|200px|'''comparison chart''' in lab2 logbook.]]
| |
| − | | |
| − | '''Record VM Installation in Lab2 (Installation Comparison Chart):'''
| |
| − | | |
| − | You will be learning to perform several different type of CENTOS Linux installs. Lab2 already has an empty table for comparing various Linux installs. You were required in lab1 to record your observation for your '''c7host''' installation.
| |
| − | | |
| − | As you proceed throughout this lab, you will be required to fill in the comparison chart for three of the VMs (virtual machines) that you will be installing.
| |
| − | | |
| − | | |
| − | '''Complete the following steps to install and run the virtual manager application:'''
| |
| − | | |
| − | | |
| − | # Launch your c7host machine, and login as as a regular user.
| |
| − | # Open a shell terminal.<br><br>'''WARNING:''' You must perform a '''yum update''' on your '''c7host''' machine before proceeding with the next steps. You issue the following command to update your software for this machine:<br><b><code><span style="color:#3366CC;font-size:1.2em;">yum update</span></code></b><br><br>
| |
| − | # You will need to download an image file for the Centos7 LIVE DVD by issuing the following command (best works while at Seneca):<br><b><code><span style="color:#3366CC;font-size:1.2em;">wget http://belmont.senecac.on.ca/centos/7/isos/x86_64/CentOS-7-x86_64-LiveGNOME-1511.iso</span></code></b><br><br>
| |
| − | # Install the virtualization software by issuing the command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">yum install qemu-kvm qemu-img virt-manager libvirt libvirt-python \<br>python-virtinst libvirt-client virt-install virt-viewer bridge-utils</span></code></b> <br><br>
| |
| − | | |
| − | {{Admon/important|Restart your Host Machine|You must restart your '''c7host''' machine after installing the virtualization program above. If you fail to do this, you may experience virtualization network problems!}}
| |
| − | | |
| − | | |
| − | ::This will install many applications (including):
| |
| − | :::* '''kvm/qemu''' - the hypervisor and other hardware emulation systems.
| |
| − | :::* A system service named '''libvirtd''' that manages the VMs.
| |
| − | :::* A graphical tool for managing virtual machines ('''virt-manager''') and the '''virsh''' command-line tool.<br><br>
| |
| − | <ol>
| |
| − | <li value="5">Start the virtualization service: <b><code><span style="color:#3366CC;font-size:1.2em;">service libvirtd start</span></code></b></li>
| |
| − | <li>The firewall configuration is altered by the addition of the virtualization software. Centos7 uses firewalld for firewall, but we will be switching back to using iptables. Issue the following series of command to install iptables and restart the firewall:<br><br> <b><code><span style="color:#3366CC;font-size:1.2em;">systemctl stop firewalld</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">systemctl mask firewalld</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">yum install iptables-services</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">systemctl enable iptables</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">systemctl start iptables</span></code></b><br><b><code><span style="color:#3366CC;font-size:1.2em;">service iptables save</span></code></b><br><br></li>
| |
| − | </ol>
| |
| − | {| width="40%" align="right" cellpadding="10"
| |
| − | |- valign="top"
| |
| − | |colspan="2"|{{Admon/important|Run virt-manager as a regular user, not as root|Otherwise all your virtual machines will be owned by root and you won't be able to use them as a regular user.}}
| |
| − | | |
| − | |}
| |
| − | <ol>
| |
| − | <li value="7">Start the graphical tool by selecting the menu options '''Applications'''>'''System Tools'''>'''Virtual Machine Manager''' or by typing the command<b><code><span style="color:#3366CC;font-size:1.2em;"> virt-manager</span></code></b></li>
| |
| − | <li>You will be learning to perform several different type of CENTOS Linux installs. Lab2 has a '''comparison chart''' for comparing various Linux installs. You were required in lab1 to record your observation for your '''centos1''' installation.</li>
| |
| − | <li>As you proceed throughout this lab, you will be required to fill in the comparison chart for the remaining 3 virtual machines that you will be installing.</li>
| |
| − | </ol>
| |
| − | | |
| − | | |
| − | === Part 2: Installing from a Downloaded Image (Centos7 LIVE CD) ===
| |
| − | {| width="40%" align="right" cellpadding="10"
| |
| − | |- valign="top"
| |
| − | |{{Admon/tip|Perform Downloads and Network installs at Seneca|'''It is recommended to perform this lab in one of Seneca College's labs'''. This lab uses servers which are on the Seneca network and which are not available from other locations (such as your home). If you attempt this lab from another location, adjust the belmont.senecac.on.ca URLs to point to another mirror server -- note that you may need to change the directory name as well as the server name. The installation of the '''centos3''' virtual machine <u>must</u> be done at Seneca.}}
| |
| − | |}
| |
| − | | |
| − | :'''VM Details:'''
| |
| − | | |
| − | :: '''VM Name (and hostname):''' centos1
| |
| − | :: '''Boot media:''' LIVE CD Image (downloaded iso file)
| |
| − | :: '''Installation source:''' Downloaded Centos7 LIVE CD image (http://belmont.senecac.on.ca/centos/7/isos/x86_64/CentOS-7-x86_64-LiveGNOME-1511.iso)
| |
| − | :: '''VM Image Pathname:''' /var/lib/libvirt/images/centos1.img
| |
| − | :: '''Memory:''' 2GB
| |
| − | :: '''Disk space:''' 10GB
| |
| − | :: '''File System (root partition):''' ext4
| |
| − | :: '''CPUs:''' 1
| |
| − | | |
| − | You do not need to burn a DVD for the Centos7 install image. You can simply download an image file (.iso), and refer to this downloaded image in order to install the Linux OS. This is the second method of installation that we will now investigate.
| |
| − | | |
| − | # Open a web-browser, click on the link below to save on your Windows machine in your Seneca Lab (Downloads section).<br><br><b><code><span style="color:#3366CC;font-size:1.2em;">http://belmont.senecac.on.ca/centos/7/isos/x86_64/CentOS-7-x86_64-LiveGNOME-1511.iso</span></code></b><br><br>
| |
| − | # Launch the VMWare Workstation application.
| |
| − | # Click on the icon to ''Create a New Virtual Machine'' and select '''Custom (Advanced)'''.
| |
| − | [[Image:vm-path.png|thumb|right|300px|When your '''centos1''' LIVE machine boots-up, immediately double-click on the '''Install to Hard Disk''' icon to run the installation program.]]
| |
| − | <ol><li value="4">'''The virtual machine will now start'''.</li><li>Immediately double-click on the icon called '''Install to Hard Disk'''.</li><li>Start timing your installation and making notes for '''centos1''' virtual machine in the '''installation comparison chart in lab2 logbook'''.</li><li>Select your downloaded iso Centos7 Gnome LIVE image (under ''Downloads'' folder) and click '''Next'''. Basically, you perform the same steps is in lab1 (i.e. select '''Custom (Advanced)''' with '''2 GB of RAM''', the VM name will be called '''centos1''' and the Hard Disk size will be '''10 GB''' (not 20GB). </li><li>When your VM boots-up, Double-click '''Install to Hard Drive'''. The installation program, similar to the one used when installing CentOS in Lab 1, will appear. You basically perform the same installation operations for this VM including for '''Date & Time''', '''Network & Hostname''', and '''Installation Destination'''. Make certain to use the '''hostname''': '''<u>centos1</u>''' as opposed to ''c7host'') for this installation. (with a few slight differences).</li><li>For '''Installation Destination''', select the destination option: '''I will configure partitioning''' and then click '''Done'''. Make certain that the '''Partition Scheme''' is set to '''LVM''' and then click on the link: '''Click to Create Automatically'''. '''Done'''. Check to make certain that the root partition has file system type: '''ext4'''.</li><li>Accept the changes and then click '''Begin Installation'''.<ol type="a"><li>You will be required to make selections very similar to what you did in lab1.</li><li>While the system is installing, take a few minutes to record your observations (including slight differences with centos1 install as opposed to c7host install).</li><li>When the installation process is complete, note the time required to install this system and record in the installation comparison chart of your lab2 logbook.<br><br></li></ol></li><li>Power-off your Centos7 LIVE system.</li><li>Restart your centos1 VM, and enter 1, 2, c, c, like you did in lab1.</li><li>Finish the final steps in the setup process (like you did in lab1).</li><li>It is recommended that you turn off the screen-saver (like you did in Lab1: [http://zenit.senecac.on.ca/wiki/index.php/OPS235_Lab_1_-_CentOS7#Turn-Off_Screen_Saver_Lock Turn-off Screen Saver Lock]).</li></ol>
| |
| − | {| width="100%" align="right" cellpadding="10"
| |
| − | |- valign="top"
| |
| − | |colspan="2"|{{Admon/important|Important Network Service Tasks|Please perform the tasks below in order allow these CentOS systems to be able to communicate with each other. '''Failure to properly perform these operations can cause problems in future labs'''.|
| |
| − | }}
| |
| − | |}
| |
| − | <ol>
| |
| − | <li value="20">Make certain to '''disable SELinux for centos1''' ([http://zenit.senecac.on.ca/wiki/index.php/OPS235_Lab_1_-_CentOS7_-_VMware#Disable_SELinux_and_Perform_Software_Updates refer to lab1])</li><li>Start and enable the SSH server to allow access to your virtual machine with these commands (semi-colon allows commands to be run in sequence):<br /> <b><code><span style="color:#3366CC;font-size:1.2em;">systemctl start sshd; systemctl enable sshd</span></code></b></li>
| |
| − | <li>Find out the IP address of your virtual machine and the name of your Ethernet network adaptor: <b><code><span style="color:#3366CC;font-size:1.2em;">ifconfig</span></code></b> </li>
| |
| − | <li>Enter the following command on your virtual machine to create a firewall exception to allow ssh traffic into the machine:<br /> <b><code><span style="color:#3366CC;font-size:1.2em;">iptables -I INPUT -p tcp -s0/0 -d0/0 --dport 22 -j ACCEPT</span></code></b></li><li>If you are logged in as root, logout to your regular user account.</li><li>Confirm that you can ssh to your virtual machine from the host (your main CentOS installation): <b><code><span style="color:#3366CC;font-size:1.2em;">ssh regularuserid@IPaddress</span></code></b> (where '''regularuserid''' is your regular user login id, and '''IPaddress''' is the '''IP_ADDRESS''' of your '''centos1''' VM!).</li></ol>
| |
| − | | |
| − | {{Admon/important|Remember to Backup your VM to USB Key!|Remember that you need to backup your '''centos1''' VM to your USB key before you leave your Seneca lab, or you will lose your work!}}
| |
| − | | |
| − | == Part 2: Installing from a Network ==
| |
| − | {| width="40%" align="right" cellpadding="10"
| |
| − | |- valign="top"
| |
| − | |colspan="2"|{{Admon/important|Authenticate to the network|The rest of this lab uses network access.''' Be sure to authenticate to the network using your browser before proceeding'''.}}
| |
| − | |}
| |
| − | | |
| − | :'''VM Details:'''
| |
| − | | |
| − | :: '''VM Name (and hostname):''' centos2
| |
| − | :: '''Boot media:''' Network installation
| |
| − | :: '''Installation source URL:''' http://belmont.senecac.on.ca/centos/7/os/x86_64/
| |
| − | :: '''VM Image Pathname:''' /var/lib/libvirt/images/centos2.img
| |
| − | :: '''Memory:''' 2048MB
| |
| − | :: '''Disk space:''' 20GB
| |
| − | :: '''CPUs:''' 1
| |
| − | | |
| − | | |
| − | # Create the VM (called '''centos2''') as you did with the ''centos1'' machine, except for the following differences:<br><br><ol type="a"><li>Select '''Network Installation''' using the installation source URL displayed above.</li><li>When customizing your partitions, do the same operation that you did in centos2, but after automatically creating the partitions, reduce the size of the root LVM partition to '''8000 MB''' and add an LVM partition with a size of '''2000 MB''' (mount point: '''/home''', name: '''home''', and make certain root and /home partitions have '''ext4''' file system).</li><li>Don't forget to install the GNOME desktop here as you will need a GUI for Centos2<br><br></li></ol>
| |
| − | # Complete the installation. Login to your regular user account, and perform a yum update for the centos2 VM (reboot if required). Make certain to adjust your screen-saver settings if desired.
| |
| − | # Repeat the steps as you did to '''start the SSH service''', '''set iptables to accept connections via ssh''', '''test connections between centos2 and centos1''', and '''disable SELinux''' (refer to lab1).
| |
| − | # Record the time taken to install, and compare this to the time taken by the previous installations. Record your findings in the Installation Comparison chart in lab2 logbook.
| |
| − | | |
| − | {{Admon/important|Remember to Backup your VM to USB Key!|Remember that you need to backup your '''centos2''' VM to your USB key before you leave your Seneca lab, or you will lose your work!}}
| |
| − | | |
| − | == Part 3: Installing from a Network using a Kickstart File ==
| |
| − | | |
| − | :'''VM Details:'''
| |
| − | | |
| − | :: '''VM Name (and hostname):''' centos3
| |
| − | :: '''Boot media:''' Network installation
| |
| − | :: '''Installation source URL:''' http://belmont.senecac.on.ca/centos/7/os/x86_64/
| |
| − | :: '''Kickstart File URL:''' http://matrix.senecac.on.ca/~andrew.smith/ops235/centos7-kickstart-v01.cfg
| |
| − | :: '''VM Image Pathname:''' /var/lib/libvirt/images/centos3.img
| |
| − | :: '''Memory:''' 2048MB
| |
| − | :: '''Disk space:''' 15GB
| |
| − | :: '''CPUs:''' 1
| |
| − | | |
| − | | |
| − | # Create the VM as you did with the ''centos2'' virtual machine, specifying a network install as before, but specify the kickstart location under the "options section" for network install. What do you think is the purpose of this kickstart file?
| |
| − | # Observe the installation. How is it different from booting from a downloaded image?
| |
| − | # Complete the installation. Record the time taken to install, and compare this to the time taken by the previous installations.<br><br>If the during the installation, you see the message at the bottom '''Pane is Dead''', click the '''Virtual Machine''' menu at the top, select '''Shut Down''' -> '''Force Off''', '''right-click''' on '''centos3''' in the ''virtual manager'' window and select '''Delete'''. Redo the VM setup for a new instance of the ''centos3'' VM.
| |
| − | # What happens when the installation is finished?
| |
| − | # Take a look at the kickstart file (eg. view url in a webj-browser) to determine the root password as well as the name and password for the first user account!
| |
| − | # Boot the virtual machine and log in (use the user ID and password information from the previous step). Compare the experience to the first time you booted the other virtual machines. Record this information in the '''table contained in Investigation 4'''.
| |
| − | # Repeat the steps as you did to '''start the SSH service''', '''set iptables to accept connections via ssh''', '''test connections between centos3 and centos1''', and '''disable SELinux''' (refer to lab1).
| |
| − | # Remember that centos3 is text-based interface only (no graphics). To recover from a blank screen, press a key (like the SPACE key) to return to the screen display.
| |
| − | # Record the time taken to install, and compare this to the time taken by the previous installations. Record your findings in the Installation Comparison chart in lab2 logbook.
| |
| − | | |
| − | | |
| − | '''Answer the Investigation 1 observations / questions in your lab log book.'''
| |
| − | | |
| − | {{Admon/important|Remember to Backup your VM to USB Key!|Remember that you need to backup your '''centos2''' VM to your USB key before you leave your Seneca lab, or you will lose your work!}}
| |
| − | | |
| − | =INVESTIGATION 2: COMMON POST-INSTALL TASKS=
| |
| − | | |
| − | ==Part 1: Perform Software Updates==
| |
| − | {|width="40%" align="right" cellpadding="10"
| |
| − | |- valign="top"
| |
| − | |
| |
| − | {{Admon/caution|Allow Time to Perform Yum Updates|Allow sufficient time in order to perform updates prior to the end of the lab. Since you will be updating ALL of your VMs, allow 15-20 "lead-time" to start your updates and to backup your VMs prior to the end of the lab. NEVER force a shut-down of your VM while updates are running, since this will ruin your VM, and you will have to restore from a backup, or redo your labs for that VM!}}
| |
| − | |}
| |
| − | | |
| − | It is important as a Linux System Administrator to update software on your Linux system periodically. Performing periodic updates will fix software bugs and inefficiencies as well as apply security patches in order to better secure your Linux server.
| |
| − | | |
| − | '''You are required to perform the following command for ALL of your 4 VMs:'''
| |
| − | | |
| − | <b><code><span style="color:#3366CC;font-size:1.2em;">yum update</span></code></b>
| |
| − | | |
| − | This will download and install all of the packages that have been updated since the installation DVD image was created. If you complete this command at Seneca, it should run quite fast as Seneca College hosts a CentOS Repository mirror (a copy of all of the current CentOS packages, on a local web server). You will be reminded at the end of each of the remaining labs to perform software updates on ALL of your VMs.
| |
| − | | |
| − | | |
| − | | |
| − | | |
| − | = LAB 2 SIGN-OFF (SHOW INSTRUCTOR) =
| |
| − | {{Admon/important|Backup ALL of your VMs!|If you have successfully completed this lab, make a new backup of all of your virtual machines onto your UBS Key.}}
| |
| − | | |
| − | ===Download and Run Lab2 Checking Script & Show Lab2 Work===
| |
| − | | |
| − | '''Perform the Following Steps:'''
| |
| − | | |
| − | # Make certain ALL of your VMs are running.
| |
| − | # Switch to your '''centos2''' VM, open a terminal, login as root, and change directory to '''/root/bin'''.
| |
| − | # Issue the Linux command: <b><code><span style="color:#3366CC;font-size:1.2em;">wget http://matrix.senecac.on.ca/~murray.saul/ops235/lab2-check-vm.bash</span></code></b>
| |
| − | # Give the '''lab2-check.bash''' file execute permissions (for the file owner).
| |
| − | # Run the shell script and if any warnings, make fixes and re-run shell script until you receive "congratulations" message.
| |
| − | #Arrange proof of the following on the screen:
| |
| − | | |
| − | ::✓ '''<u>All</u> VMs''':<blockquote><ul><li>All 4 VMs '''created''' and '''running'''</li><li>'''Disk layout''' and '''size''' correct on ALL virtual machines</li><li> Proof of '''yum updates''' on ALL VMs</li></ul></blockquote>
| |
| − | ::<span style="color:green;font-size:1.5em;">✓</span>'''centos2 VM''':<blockquote><ul><li>Creation of your bash shell script called '''myreport.bash'''</li><li>A list of your '''iptables''' rules (command: '''iptables -L''')</li><li>Output from running the '''lab2-check.bash''' script with all OK messages</li></ul></blockquote>
| |
| − | ::<span style="color:green;font-size:1.5em;">✓</span> Lab2 logbook notes and '''Installation Comparison chart''' completed.
| |
| − | | |
| − | = Practice For Quizzes, Tests, Midterm & Final Exam =
| |
| − | | |
| − | # What is the name of the CentOS installation program?
| |
| − | # What is the name of the file created by the CentOS installation program?
| |
| − | # Which type of installation works best for confirming compatibility with hardware before installation? Why?
| |
| − | # Which type of installation works best for installing large numbers of computers? Why?
| |
| − | # How can you reduce the number of software updates required immediately after installation?
| |
| − | # How do you start and stop virtual machines?
| |
| − | # How do you SSH into your virtual machines?
| |
| − | # List 2 ways that you can access your root account
| |
| − | # What is the difference between the commands '''su''' and '''su -''' ?
| |
| − | # What is the home directory for the user "root"?
| |
| − | # How do you determine the host name of your GNU/Linux workstation?
| |
| − | # What command can display the NIC's MAC address?
| |
| − | # What command is used to get a list of running processes on your newly-installed system?
| |
| − | # How create in a shell script to force the user to run shell script as root?
| |
| − | # How to store each file-name in your current directory as separate positional parameters? How to list all of the positional parameters? How to display the number of positional parameters? | |
| − | | |
| − | | |
| − | [[Category:OPS235]]
| |
| − | [[Category:OPS235 Labs]] | |
