There are many other tasks that a The Linux system administrator must perform other than OS you will be installing Linux and installing softwarein this lab will be a Host Machine (''hostname'': '''c7host''') that will allow you to run '''Virtualization Software''' to create 3 separate virtual machines (to be performed in lab2). A few additional tasks are user management and managing servicesIt is important to install this host machine correctly since other labs will depend on the stability of this host machine.

:* Administer '''Correctly install the CentOS 7 FULL INSTALL DVD'''(add, remove, modifynot LIVE DVD) userson your removable hard disk. :* ''' on Record installation characteristics of CentOS 7 FULL INSTALL''' in a Linux systemchart (contained in lab2 logbook chart) to compare with other installation methods performed in lab2. :* Save time while adding new users using a template of '''start-up filesVerify correct settings'''prior to proceeding with host installation stages. :* Create and manage '''groupsObtain Linux server information after installation''' on to create a Linux systemsoftware asset report for later access. :* '''Start and Stop servicesDisable Linux Kernel security enhancements''' on to allow easier internal networking connections (to be reactivated in a Linux systemlater lab). :* Display the Observe that '''status of running servicesBash Shell Scripts can automate routine tasks''' on a Linux system.

{|cellpadding- valign="15" width="40%top"

| [[Image:blank- valign="top"cd.png|thumb|left|75px|<b>CentOS 7</b>FULL INSTALL DVD]]

|width="10%" | [[Image:harddrive.png|thumb|left|85px75px|<b>Removable Hard Disk Pack</b> (SATA)]]

|width="10%" |[[Image:ubs-key.png|thumb|left|85px75px|<b>USB key</b><br>(for backups)]]

|width="10%" |[[Image:log-book.png|thumb|left|70px60px|<b>Lab4 Lab Log Book</b><br>(labs 1 & 2)]]

{|width="50100%" cellpadding="15"

|width="10%" |<u>User Package Management:</u>[http://unixhelp.ed.ac.uk/CGI/man-cgi?useradd+8 useradd]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?userdel+8 userdel]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?usermod+8 usermod]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?groupadd+8 groupadd]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?groupdel+8 groupdel]|width="10%" |<u>Managing Services</u>[http://unixhelp.ed.ac.uk/CGI/man-cgi?chkconfig+8 chkconfig]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?service+8 service]<br>[http://www.dsm.fordham.edu/cgi-bin/man-cgi.pl?topic=systemctl systemctl]<br>|width="10%" |<u>Miscellaneous</u>[http://man7rpm.org/linux/manmax-pages/man5rpm/passwdrpm.58.html /etc/passwdrpm]<br>[http://man7.org/linux/man-pages/man5man8/groupyum.58.html /etc/groupyum]|<bru>[http://man7.org/linux/man-pages/man5/shadow.5.html /etc/shadow]System Information<br>[http://archive.linuxfromscratch.org/blfs-museum/1.0/BLFS-1.0/postlfs/skel.html /etc/skel]<bru>[http://zenit.senecac.on.ca/wiki/index.php/Init_vs_systemd init vs systemd]|}

= INVESTIGATION [http://man7.org/linux/man-pages/man8/ifconfig.8.html ifconfig]<br>[http://man7.org/linux/man-pages/man8/netstat.8.html netstat]<br>[http://man7.org/linux/man-pages/man8/route.8.html route]<br>[http://linux.die.net/man/1: User/Group Management =nslookup nslookup]<br>|<u>Miscellaneous</u>

User account management is a very important operation that a Linux sysadmin does on a consistent basis[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. The sysadmin not only needs to add or remove user accounts by issuing commands, but may need to automate user account creations a large number (batch) of potential employees1. There are many features with the Linux command to create new users includinghtml more]<br>[http: specification of a home directory, type of shell used, name, password and time//man7.org/linux/man-limit (referred to as "aging") for a new user accountpages/man1/file.1. Remove user accounts also have options such as removing the user account but keeping the home directory for reference or evidence of "wronghtml file]<br>[http://man7.org/linux/man-doing"pages/man1/wget.1.html wget]<br>[http://man7.org/linux/man-pages/man1/chmod.1.html chmod]<br>[http://man7.org/linux/man-pages/man1/scp.1.html scp]<br>[http://ss64.com/vi.html vi]

In your ULI101 course, |width="40%"|{{Admon/tip|Online Hands-on Linux Tutorials (recommended)|The following online tutorial will allow you learned to change permissions for directories and files relating to user, same group members and other group members. In this course, since practice Linux commands that you are the sysadmin with root privileges, you can create or remove groups learned from ULI101 as well as change essential shell scripting skills. Login to your '''Matrix''' account, and issue the ownership of directories and files! We will now learn pathnames to perform key user account management operations run the online tutorial in this sectionMatrix:<br><ul><li>Using the vi Text Editor:<br>'''/home/murray.saul/vi-tutorial'''<br><li>Linux Basics:<br>'''/home/murray.saul/linux-basics'''</li><li>Shell Scripting - Part I (Scripting Basics):<br>'''/home/murray.saul/scripting-1'''</li></ul>|}}|}

== Part INVESTIGATION 1: The /etc/passwd file =CREATE HOST MACHINE (c7host)=

# Look at For the next 3 investigations, you will learn how to install your Centos Full DVD onto your removable hard disk. You will customize your install to setup several separate partitions:<bul><codeli><span style='''/''' (The "color:#3366CC;font-size:1.2em;root"partition)</li>/etc/passwd<li>'''/span>home''' (Store regular user accounts)</codeli></bli> file.# Make note of the contents of that file.# Read about the file: http://man7.org'''/linuxvar/man-pageslib/man5libvirt/passwd.5.html # Make sure you know what information each field contains.# Why do you think there are so many users?# Look at the names of the users. What do you think these user names represent? Are they people?# What is the numeric user ID images''' (UIDstore virtual machine images to be created in lab2) of the root user?# The user IDs of real users </li><li>'''swap''' partition (peopleVirtual Memory) are different from the user IDs of system accounts. What is the pattern?</li></ul>

Make certain to record your observations of this install in the comparison chart for '''c7host'''Answer the Part 1 observations / questions in your lab log booklab2 logbook.'''

== Part 21: Adding users Start Installation ==

::'''Answer the Part 2 observations <u>Host Machine Details:</ questions in your lab log book.u>'''

== Part 3: Managing Groups ==:*'''Name:''' c7host::*'''Boot media / Installation:''' CentOS7 Full Install DVD::*'''Memory:''' 8GB::*'''Disk space:''' 250GB (or higher)::*'''CPUs:''' 1

#Remain in your '''centos1''' VM for this section.# Read the man page for the <b><code><span style{| width="color:#3366CC;font-size:1.2em;40%">groupadd</span></code></b> and <b><code><span stylealign="color:#3366CC;font-size:1.2em;right">groupdel</span></code></b> commands.# Note which option allows you to set the Group ID number ('''GID''') when you create a new group.# Examine the file <b><code><span stylecellpadding="color:#3366CC;font-size:1.2em;10">/etc/group</span></code></b>#* Which values of GID are reserved for system accounts?#* Which values of GID are reserved for non-system user accounts?#* What is the lowest available GID number for non|-system users?#* What is the default group name of a new user?#* Add a new group named <b><code><span stylevalign="color:#3366CC;font-size:1.2em;top">ops235</span></code></b> with a GID of <b><code><span style|colspan="color:#3366CC;font-size:1.2em;2">600<|{{Admon/span></code></b>.#* The management at your organization have concerns regarding some irresponsible users on your system.#** Add a new group named '''investigation'important |You''.#** Look at '''/etc/group''' and note the GID of group called '''investigation'''.#** What GID is given re supposed to a new group use this hard drive only for this course| But if you do not specify really need to use it?#** In the filefor two courses, add those users to and the end of professor for the concerned group other (separate each userprobably windows) course will allow it -name ask your professor for help with a comma)partitioning.}}|- valign="top"#** Those individuals have explained their actions to management and the crisis has been resolved|[[Image:lab2-logbook. Delete the png|thumb|right|100px|'''investigationcomparison chart''' groupin lab2 logbook.]]#** Look at |[[Image:installation_summary.png|thumb|right|400px|The '''/etc/groupInstallation Summary''' again and note the changescreen provides flexibly when configuring to install on your computer.]]|}

# Refer to this listing of installation screenshots if you need a reference:<br>[ [http://matrix.senecac.on.ca/~murray.saul/ops235/installation/ installation screenshots] ]<br># Insert your '''removable SATA hard disk''' into the drive tray.# Set your computer's drive selector switch to '''external''' (a.k.a ''position #4'').# Power up the computer and insert the '''CentOS 7 Installation DVD''' into the DVD drive, then power-off computer.# Determine if your computer is the <u>newer</u> or <u>older</u> model. '''Newer computer models''' are labelled '''HP Z230'''.<br><br>'''NOTE:'Answer '' If you are using the Part 3 observations '''<u>newer</ questions u>''' model, allow the computer to boot up (<u>without</u> pressing F10 key) to boot from DVD. For <u>'''older'''</u> models, press F10, press ENTER for password, and select the DVD drive. Refer to the comparison chart in your lab2 lab log booklogbook, and fill in various installation information for '''c7host''' while you perform the installation (such as time it took to perform a full install, installation options, etc).<br><br>'''WARNING:''' Only use the same type of computer (only the <u>'''newer'''</u> computer or only the <u>'''older'''</u> computer) when working in the Seneca labs for the duration of this course!<br><br><ol> <li value="6">Select the option '''Test this Media & Install Centos7'''. Your DVD will be checked for defects.</li> <li>If the check is successful, you will be prompted for a language. In the first screen, select language '''English''' with subselection '''English-Canada''' and then click the '''Continue''' button on the bottom right-hand screen.</li>

== <li>The '''Install Summary''' should now appear. This screen allows the installer to customize their Centos7 system prior to installation.</li> <li>Configure the following installation settings from the ''Install Summary Screen'':<br><br><b>DATE & TIME:</b><ul><li>Click on the Map to select Toronto area (you may also select from the drop-down menu section)</li><li>Click the <b>DONE</b> button at the top-left corner to finish and return to the Installation Summary screen.</li></ul><br><b>NETWORK & HOSTNAME:</b><ul><li>Select the default Ethernet connection and click the button on the top right-hand side to change the setting from <b>OFF</b> to <b>ON</b>.</li><li>At the bottom left-hand corner type the hostname: <b>c7host</b> (all lowercase letters)</li><li>Review your settings, then click the <b>DONE</b> button at the top-left corner to finish and return to the Installation Summary screen.</li></ul><br><b>SOFTWARE SELECTION:</b><ul><li>Select the software packages labelled: <b>Gnome Desktop</b></li><li>Click the <b>DONE</b> button at the top-left corner to finish and return to the Installation Summary screen.</li></ul><br></li> <li>Although the Centos installtion program can provide suggestions on how to partition your hard disk, you will be customizing partitions for your hard disk. This custom partitioning is important since it will have consequences on future labs that you perform (especially for lab2).<br><br>Proceed to '''Part 4: Deleting 2''' to customize your partitions.</li></ Modifying Users ==ol>

'''Answer the == Part 4 observations / questions in your lab log book.'''2: Custom Partitioning ==

{|width=INVESTIGATION 2"40%" align="right" cellpadding="10"|- valign="top"|{{Admon/tip|Mount Points and Linux File System Types|Similar to other Operating Systems like windows '''fat''' / '''vfat''' / '''ntfs''' file system types, it is good to know a few common file system types in Linux for comparison: Managing System Services <br><ul><li><b>xfs:</b> &nbsp; Newer filesystem (fast transfer rates for large files, Journaling)</li><li><b>ext4:</b> &nbsp; Newer filesystem supporting large files and RunJournaling (used in for this lab)</li><li><b>ext2:</b> &nbsp; Stable filesystem popular for databases (no journaling)</li></ul>|}}|-levels|[[Image:partition_verification.png|thumb|right|550px|Carefully verify partition mount-names and sizes prior to proceeding with install. Check [http://matrix.senecac.on.ca/~murray.saul/ops235/installation/ installation screenshots] link for verification.]]|}#From the installation summary screen, click '''Installation Destination'''.#In the installation destination screen, select the destination option: '''I will configure partitioning''' and then click '''Done'''.#The manual partitioning screen should appear.#If you have used your hard disk for previous Linux (Centos) distributions, you should remove them. Click on the distribution, and for each partition, select the partition and click the remove button (minus sign) and confirm deletion.#Change the option '''New mount points will use the following partition scheme''' from '''LVM''' to '''<u>Standard Partition</u>''' (you will not be using LVM for your c7host machine).#Before you proceed with creating partitions, let's see the partitions that we need to create for our host computer:<ul><li>Primary Partitions (ext4):<ul><li>'''30GB''' for '''/''' (i.e. "root")</li><li>'''40GB''' for /home</li><li>'''100GB''' for '''/var/lib/libvirt/images''' </li></ul> </li><li>Swap Partition:<ul><li>'''16GB''' (Note: "swap" must be selected from the drop down menu)</li></ul></li></ul><br>'''NOTE:''' Remember that the sizes are recorded in MB (eg. 30 GB =30000 MB) and you should multiply GB by a factor of 1024 to get the correct size.<br> (eg. '''30 GB x 1024 = 30720 MB''')<br><br>#We will now create the root (/) partition. '''Click on the add button (plus) sign'''.<br>#In the '''Add a New Mount Point''' screen, select '''/''' as the mount-point (either by typing or selecting from drop-down menu), and enter '''30720''' in for partition size and click '''Add Mount Point''' button.#Repeat the same steps above for the '''/home''' partition and '''/var/lib/libvirt/images''' partition. You need to type the ''/var/lib/libvirt/images'' partition since it does not appear in the drop-down menu.#Select each of the created partitions, and make certain that the file-system type is changed from '''xfs''' to '''ext4'''.#Finally, add a swap partition (Mount Point: swap) for '''16 GB'''.#Check that your partition settings are correct (you can ask your instructor or lab monitor to confirm), and then click '''Done''' to proceed.#A Summary of Changes screen will appear to show the partitioning operations that will be created. Click the '''Accept Changes''' and click '''Begin Installation''' in the Installation Summary screen to proceed with the installation.#Start timing your host machine installation.

The process may not be hard, but knowing how to stop, start, restart and check == Part 3: Completing the status of services is absolutely critical to a Linux server. '''Aside from learning to trouble-shoot problems''' by checking the status of running services, '''understanding how to manage services is critical to help protect a Linux server from penetration''' (this term is referred to as "'''Hardening a system'''"). Sometimes it is "what we don't know" that can harm us. One key element in hardening a computer system is to disable non essential networkng services to allow IDSs ('''Intrusion Detection Systems''') to focus on a narrower range of policy violations. A Debian-based penetration testing distribution called Kali (formerly referred to as '''BackTrax''') allows sysadmins and security professionals to identify vulnerabilities in their computer systems, and thus improve (harden) their systems against penetration. Learning to monitor the status, enable and disable networking services underlies the '''Backtrax''' motto:<br><br>'''''"The quieter you are, then more you will hear..."'''''<br><br>Installation ==

{|width="40%" align="right" cellpadding= Part 1"10"|- valign="top"|[[Image: How completed.png|thumb|right|500px|This screen indicates that installation is complete. You should remove the install DVD and confirm Centos7 boots from your removable hard drive. ]]|}#During the installation process, you will required to create a '''root password''' (for administration access) and create a '''regular user account'''. Click on '''Root Password''' and enter your root password. Think of an appropriate password and record that password somewhere in case you forget! An indicator will appear to show you how secure your password is. Retype your root password and click '''Done''' (you may have to click Done <u>twice</u> if your password is not considered to be a strong password).#You need to create a regular user account. This account will be used to graphical log into your host machine. It is never recommended to graphically log into a graphical Linux/Unix system as root. It is better to log into a regular user account, then run a command to login as root (you will learn how to do we Manage System Servicesthis later in this lab).#Click '''User Creation''' and enter your '''full name''', '''username''', and an appropriate '''password''' (and confirm password). Click '''Done''' to finish (click twice if password is not considered to be a strong password).#Remember to record this host installation information in the '''installation comparison chart''' in the lab2 logbook.#When installation is complete, you will notice a message at the bottom of the screen stating: '''CentOS is now successfully installed and ready for you to use!'''#Click the Reboot button. Your DVD will <u>briefly</u> open in the DVD drive bay. Make certain to remove this installation DVD so that Centos will boot from your hard drive.#After the system reboots, a boot menu should briefly appear, then prompt the user to accept the License Information (what is the purpose of accepting the license?).#Click on '''License Information''' and '''click that you agree to the license agreement''', click '''Done''' and then click '''Finish Configuration'''.#Click Forward to enable Kdump (what is the purpose of this application? ).#The system should then graphically prompt the user to login with their regular user account. Click on your '''regular user account name''' and '''enter your regular user password'''.<br><br>#The last phase of the installation process should now run:<ul><li>Confirm English as the default input source and click '''Next'''.</li><li>Skip the creation of online accounts by clicking '''Next'''.<li>Start using your installed Linux system by clicking '''Start Using CentOS Linux'''.</li></ul><br>#Stop timing your installation and note the amount of time that your installation took to perform. Also take the time to fill in the c7host section of the installation comparison chart in your lab2 logbook.#Open a web-browser and check to see if you can connect to the Internet.<br><br>#Your system automatically enables a '''screen-saver''' application which is a useful security tool to prevent unauthorized viewing of information on a terminal after a certain amount of inactivity. If you find this feature annoying and want to turn it off or adjust the idle time perform the following steps:<ol type==="a"><li>Click on your '''username at the top right-hand screen'''</li><li>Select '''Settings''' from the drop-down menu</li><li>Click the '''Power''' icon located in the ''Settings'' Dialog Box</li><li>Change the amount of time in the '''Power Saving''' section to '''Never''' or a '''longer period of time'''</li><li>Close the ''Settings'' Dialog box.<br><br></li></ol>#Proceed to Investigation 2 to obtain basic information from your newly installed Centos Host machine.

We have seen that maintaining unneeded '''packages can be a security risk''' due to the unnecessary increase Answer Investigation 1 observations (all parts and questions) in the complexity of your systemlab log book. Similarly, it is also unnecessarily hazardous, and even more so, to leave unneeded services running. In this investigation, we will learn how to '''control services, and turn off those services that we think are not necessary to help reduce security risks'''.}}

'''Answer Part 1 observations / questions in your lab log book.'''=INVESTIGATION 2: OBTAINING HOST MACHINE SYSTEM INFORMATION= 

{|width="40%" align="right" cellpadding=Part 2"10"|- valign="top"|{{Admon/important|Accessing the Administration Account (root)| Many administrative tasks require the root administrative account. There are many ways to access this administration account: How do we Manage Runlevels?===<ul><li>Login: '''root''' (enter root password)</li><li>Switch User to root (without login):<ul><li>'''su''': Remains in regular user's directory, does not run root's startup script(s).</li><li>'''su -''' : Changes to root's home directory (/root) and runs root's start script(s).</li></ul></li></ul>}}|}Navigate through your Graphical CentOS system, '''locate and run a terminal program (in order to issue Linux commands). Issue and record the commands used and the output generated in each of the following steps:'''

Running servers in #With older (ancient) versions of Linux, a user once may have been allowed to login to their graphical mode Linux system using '''root''' as their user-name and their root password. This has been determined to be a security risk and that option has been removed with many or all Linux operating systems.#Therefore, from this point onwards, you will make be logging into your system most likely regular user account instead and issuing a command to login as the ''root'' user. #Refer to the Information box regarding how to access the admin account from the command line.#Issue the command <b><code><span style="color:#3366CC;font-size:1.3em;">su </span></code></b> Issue the '''pwd''' and '''whoami''' commands to be penetratedconfirm your directory pathname. When finished logout of this account.#Issue the command <b><code><span style="color:#3366CC;font-size:1. The X3em;">su -windows framework can be vulnerable </span></code></b> Issue the '''pwd''' and '''whoami''' commands to attacks when these servers confirm your directory pathname. What do you notice are connected the main differences between using '''su''' versus using '''su -''' ?# An installation log file called <b><code><span style="color:#3366CC;font-size:1.2em;">/var/log/anaconda/anaconda.packaging.log</span></code></b> has been created to record the Internetinstallation of your c7host machine. This file is why when an ASCII file which can be viewed with the <b><code><span style="color:#3366CC;font-size:1.2em;">more</span></code></b> command. # You can make use of this file to determine how many packages have been installed: complete the following command to count the number of packages that are labelled "Installing" in the installation log file::: <b><code><span style="color:#3366CC;font-size:1.2em;">grep -i installing /var/log/anaconda/anaconda.packaging.log | wc -l'''</span></code></b><ol> <li value="8">Issue that command displayed above. Does it work? If not, what account do you think you should be in? When you get the command working record this important information regarding commands and the admin account in your lab logbook.</li> <li>Using the <code>rpm</code> command: you install server versions can also use the following commands to list all the installed packages, and the total number of Linuxpackages installed:</li></ol>::<b><code><span style="color:#3366CC;font-size:1.2em;">rpm -q -a'''</span></code></b>::<b><code><span style="color:#3366CC;font-size:1.2em;">rpm -q -a | wc -l'''</span></code></b>::<b><code><span style="color:#3366CC;font-size:1.2em;">rpm -qa | wc -l'''</span></code></b><ol> <li value="10">The <code>'''-q'''</code> option means query, they work and the <code>'''-a'''</code> option means all (in text-based mode onlyother words, query all installed software packages). Desktop versions Did you get the same number of packages from the above two methods?</li> <li>Some of Linux are then the files on your system were installed on workstations with the software packages, and some were created by system activity (working for example, by creating your Learn account and by logging in graphical mode) that connect to . If you know the server package name (for security reasonsfrom the <code>install.log</code>), you can list all the files that were installed from the package by using the following command:</li></ol>::<b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;font-size:1.2em;">rpm -q -l gedit</span></code></b>

The Linux sysadmin can also change <ol><li value="12">Issue the following command to obtain the runtotal number of files installed for gedit:<br><br></li></ol>::<b><code><span style=" pointer-level (or state) of a graphical Linux server to run in textevents:none;cursor:default;color:#3366CC;font-based mode and run the graphical mode by issuing a command when graphic mode is requiredsize:1. The run2em;">rpm -level term is now deprecated ql gedit | wc -l</span></code></b><ol> <li value="13">Using what you learned in Fedorasteps 3, 4, and will likely be deprecated in RHEL7, get a count of the total number of files installed by all of the software packages on your system.</CentOS at some point as well, but for now li><li>How can you explain why this number is what a lot larger than the industry is usingtotal number of packages installed? Record your answer in your lab logbook.</ol>

#Perform this part {|width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/important|Pathname for USB Stick|The default mount location has been changed in both your linux distributions newer than CentOS. So while we will get '''centos2/media/usb-device-name''' and , in newer distributions you'll see '''centos3/run/media/userloginid/usb-device-name''' VMs}}|}#To find out the name that you have assigned to your Linux system, enter the command: <b><code><span style="color:#3366CC;font-size:1.2em;">hostname</span></code></b>#To find out the kernel version of your GNU/Linux workstation and the date it was created, enter the command:<olbr><b><code> <li valuespan style="2color:#3366CC;font-size:1.2em;">Issue uname -rv</span></code></b>#To find out all the following system processes running on your GNU/Linux workstation, enter the command: <ulb><code><span style="color:#3366CC;font-size:1.2em;">ps -ef</span></code> <li/b>#We will now collect networking information for your installed system.#To check the network configuration settings obtained from the DHCP server, run the following commands, describing the output in your log book:::: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">runlevelifconfig</span></code></b>::: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">route -n</span></licode></b> :::<b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">nslookup</ulspan> </licode> <li/b>Note (at the difference in output between ''nslookup'centos2'prompt, enter the word '' and '''centos3server'''and record the output. Type exit to leave nslookup).</liol> <livalue="8">You can use Find the '''init''' command to change following information in the current run-level. See a list output of runlevels [httpsthe above commands:</li></wwwol>::: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.centos.org2em;">MAC address</docsspan></5code></htmlb> of the ethernet network interface:::<b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">Subnet mask</5.2span></Installation_Guidecode></s2b>::: <b><code><span style="pointer-initevents: none;cursor: default;color:#3366CC;font-boot-shutdown-rl.html here]size:1.2em;">The IP address </span></licode><li/b> Use the '''man''' command (assigned to learn how to use you by the '''init''' command. Use this command to change the current runDHCP server)::: <b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-level in '''centos2''' to '''3'''size:1. What happened?2em;">The default gateway</span></licode></b> ::: <b><licode>Issue the following Linux command<span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">The DNS nameserver</span></code></b> <ulol> <livalue="9">Run the commands <b><code><span style="color:#3366CC;font-size:1.2em;">startxhostname</span></code></b>, <b><code><span style="color:#3366CC;font-size:1.2em;">uname -rv</lispan></code> </ulb> , <b><code><span style="color:#3366CC;font-size:1.2em;">ps -ef</lispan> <li/code>What happens?</lib>, <b> <licode>Log<span style="color:#3366CC;font-off your graphical system. You should return to your shell promptsize:1.2em;">ifconfig</span></licode> <li/b>Using systemd requires a different method of setting text mode , and graphical mode<b><code><span style="color:#3366CC;font-size:1. You can refer 2em;">route -n</span></code></b> redirecting the output to this link for future referenceadd to a file in root's home directory called <b><code><span style="color: [http#3366CC;font-size:1.2em;">system.txt</span></fedoraproject.orgcode></wiki/Systemd#How_do_I_change_the_runlevelb>.3F How to Change Run-Levels with Systemd]</li><li>Restart your centos2 machine, and make certain that it runs in Copy the installation log file <code>'''graphical/var/log/anaconda/anaconda.packaging.log''' mode</licode> </li>Why would you want and the file '''system.txt''' to a USB memory key, or '''scp''' to make your matrix account as a graphical Linux system run in text-based mode?backup.</li></ol>

'''Answer Part the Investigation 2 observations / questions in your lab log book.'''

==Automating Routine Tasks (Shell Scripting)Part 1: Disable SELinux and Perform Software Updates== 

{{Admon/tipimportant|Bash Shell Scripting Tips:SELinux|<br><ul><li>SELinux stands for '''The case statement:Security-Enhanced Linux'''<br><br>The case statement . It is a control-flow statement component that works in a similar way as helps to better secure the if-elif-else statement system to protect against intrusion (but is more concisehackers). This statement presents scenerios or "cases" based on values or regular expressions (not ranges SELinux is enabled upon the default install of values like if-elif-else statements)CentOS. After action(s) are taken for SELinux can be a particular scenerio (or "case")good thing, a break statement (''';;''') is used to "break-out" if you take care of the statement (it and not perform other actions)know how it works. A default case (*) For this course it is also used to catch exceptions.<br><br><u>strongly recommended that you '''Examples (try in shell script):'''</u><br><br>''read -p "pick a door (1 or 2): " pick<br>case $pick in<br>&nbsp; 1) echo "You win a car!" ;;<br>&nbsp; 2) echo "You win a bag of dirt!" ;;<br>&nbsp; *) echo "Not a valid entry"<br>&nbsp;&nbsp;&nbsp;&nbsp; exit 1 ;;<br>esac''<br><br>''read -p "enter a single digit: " digit<br>case $digit in<br>&nbsp; [0-9]) echo "Your single digit is: $digit" ;;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; *)&nbsp;echo "not a valid single digit"<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; exit 1 ;;<br>esacdisable SELinux by default''<br><br></li><li>'because we won''The getopts function:'''<br><br></li></ul>The getopts function allows t have the shell scripter time to create scripts that accept options (like options for Linux commands). This provides reconfigure it every time the Linux administrator with scripts that provide more flexibility and versatility. A built-in function called '''getopts''' (i.e. get command options) is used in conjunction with a '''while''' loop and a '''case''' statement to carry out actions based on if certain options are present when the shell script is run. The variable '''$OPTARG''' can be used if an option accepts text (denoted in the getopts function with an option letter followed by a colonlabs make it necessary. Case statement exceptions use the ''':)''' and '''\?)''' cases for error handling.<br><br>'''<u>Example of getopts</u>''' (try in script and run with options)<br><br>''while getopts abc: name<br>do<br>&nbsp; case $name in<br>&nbsp; &nbsp; a) echo "Action for option \"a\"" ;;<br>&nbsp; &nbsp; b) echo "Action for option \"b\"" ;;<br>&nbsp; &nbsp; c) echo "Action for option \"c\""<br>&nbsp; &nbsp; &nbsp; &nbsp; echo Value is: $OPTARG" ;;<br>&nbsp; &nbsp; :) echo "Error: You need text after -c option"<br>&nbsp; &nbsp; &nbsp; &nbsp; exit 1 ;;<br>&nbsp; &nbsp; \?) echo "Error: Incorrect option"<br>&nbsp; &nbsp; &nbsp; &nbsp; exit 1 ;;<br>esac''<br><br>}}

{|width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/tip|Bash Shell Scripting Tips:|<br><ul><li>'''She-bang line: #Download!/bin/bash'''<br><br>Shell scripts have evolved of the past 40 years. To avoid running a newer shell script on an older shell, it is recommended to force running the shell script in the correct shell. In order to do this, studyon the first line at the very beginning of the shell script, you add the '''#!''' ('''# as in "shhhh" - a comment''', and ''' ! is referred to as "bang" run a commmand''': in this case, '''run the command: /bin/bash'''). You can issue the Linux command '''which bash''' to get the correct location. If there is no bash shell on that machine, the shell script will not run (as a precaution - the Linux admin will know how to make a fix to the following shell scriptif required)<br>. </li><li>'''Variables:'''<br><br> There are 3 types of variables that can be used in shell scripting: '''ENVIRONMENT''' (eg. $USER), '''user-defined''' ($varName), and '''positional parameters''' (eg. $1, $2... containing arguments after shell script or by using set command (eg. Issue '''set $(ls)''' ). Using dollar sign ('''$''') in front of variable expands the command:value assigned.<br><bbr><code/li><span style=" pointer-eventsli>'''Command Substitution:none;cursor'''<br><br>A very useful trick to take output from a command to be used as an argument for another command. Examples include:default<br>'''file $(ls)'''<br>'''set $(ls);color:echo $#3366CC;font-sizeecho $*'''<br>'''echo "hostname:1.2em;$(hostname)"'''<br><br><li>wget https'''Logic Control Flow Statements://scs'''<br><br>The '''test''' command can be used to see if a condition is true or false<br>(i.e.senecactest $USER &#61; "root") .onThe '''$?''' special shell variable stores the result (zero if true, non-zero if false).caSquare brackets '''[ ]''' can be used to represent the test command with the condition <u>inside</~murrayu> the brackets (spaces separating brackets).saulCan use '''if''' / '''if-else''' /user'''if-elif-createelse''' statements with brackets.bashThe '''exit''' command can be used to terminate the shell script with a false value.<br><br>'''<u>Examples</spanu>'''<br><br>''if [ $USER &#61; "root" ]''<br>''then''<br>&nbsp;''echo "You must be root" >&amp;2''<br>&nbsp;''exit1''<br>''fi''<br><br># For number comparison: use:<br># -gt,-ge, -lt, -le, -eq, -ne<br><br>''if [ $age -gt 65 ]''<br>''then''<br>&nbsp;''echo "retire"''<br>''else''<br>&nbsp;''echo "don't retire"''<br>''fi''<br><br>''if [ $grade -gt 79 ]''<br>''then''<br>&nbsp;''echo "You get Good Mark"''<br>''elif [ $grade -gt 49 ]''<br>''then''<br>&nbsp;''echo "You pass"''<br>''else''<br>&nbsp;''echo "You fail"''<br>''fi''<br></codeli></bul>}}#Try to understand what these |}You may have learned about creating and running Bash Shell Scripts in your ULI101 course. Shell scripts do, help Linux users and system administrators to automate repetitive tasks to become more efficient and to help them save time. You will be reviewing and then run the building a basic Bash Shell script as rootto generate information reports for your newly-installed Linux host machine. After running the shell script, Take time to view Shell Scripting Tips which are located on the contents of the '''/home''' directory to confirmright-hand side.

Although Perform the '''zenity''' command is a "user-friendly" way to run shell scripts, Linux administrators usually create shell scripts that resemble common Linux commands. In this lab, you will learn to create a shell script using the getopts function to make following steps in your shell script behave more like actual Linux commands (including the use of options). Refer to the notes section on the right-hand-side for reference about the '''case''' statement and the '''getoptsc7host''' function.machine:

&#35;!/bin/bash <br>

if [ $PWD USER != "/root" ] # only runs if logged in as root's home directory<br>then<br>&nbsp;echo "You must be logged in as root's home directory." >&2<br>

<ol><li value="64">Save your editing session, but remain assign the '''myreport.bash''' file read and execute permissions (at least for the owner) and run by typing:<br><b><code><span style="color:#3366CC;font-size:1.2em;">./myreport.bash</span></code></b></li><li>Did it run? If not what do you think you need to do in order to run the text editor.Bash Shell Script?</li><li>The Issue the command <b><code displayed below uses ><span style="color:#3366CC;font-size:1.2em;">su -</span></code></b> and run the getopt function set script from the input file pathname or check for invalid options or missing option textregular user's home directory (not root's home directory):<br><b><code><span style="color:#3366CC;font-size:1.2em;">~regularuserid/myreport. Add the following bash</span></code></b></li><li> Did it work?</li><li>Reopen your text-editing session for '''~regularuserid/myreport.bash''' and add the following lines of code to the bottom of the shell script file:</ol>

outputFlag=echo "nSYSTEM REPORT"> /root/report.txt<br>while getopts iecho "Date: name<br>do<br>&nbsp;case $name in<br>&nbsp; &nbsp;i(date +'%A %B %d, %Y (%H:%M:%p) inputFile=$OPTARG ;;<br>&nbsp; &nbsp;:') echo "Error: You need text after options requiring text"<br>&nbsp; &nbsp; &nbsp; &nbsp;exit 1 ;;> /root/report.txt<br>&nbsp; &nbsp;\?) echo "Error: Incorrect option"<br >&nbsp; &nbsp; &nbsp; &nbsp; exit 1 ;;<br>&nbsp;esac<br>done/root/report.txt<br>

<br><ol><li value="68">Save your editing sessionand run the bash shell script. View the contents of the file called '''report.txt''' that was generated (I hope you are using the up arrow key to issue previously issued commands in order to save time!). Notice how the redirection symbol &gt; is used at the beginning of the report, but remain in and then the other redirection symbol &gt;&gt; is used to help "grow" the report with the text editorother content.</li><li>The code displayed below uses logic to exit only remaining content of the script if report would be the input file does not existsystem information. Command We can use a shell scripting trick called "command substitution is used to store each line of the input file as a positional parameter" $( . There is one subtle problem here: The full names of the users contain spaces which can create havoc when trying to set each line as a separate positional parameter. In this case the sed ) in order place results from an command is used to convert spaces to plus signs (+), which will be converted back later. Finally, a '''for''' loop is used to create each account by another command ('''useradd'''like echo) . Re-edit the shell script and mail the user their account information ('''mail'''). Add add the following codeat the bottom of the shell script file:</li></ol>

if [ ! -f $inputFile ]<brol>then<br>&nbsp; echo li value="The file pathname \10"$inputFile\>Save, run the script, and view the ''report.txt'' contents (are you using tip that was given to save time?).</li><li>Edit the shell script and include output from the <b><code><span style=" is empty or does not existcolor:#3366CC;font-size:1.2em;" >&2ps aux<br/span></code></b>&nbsp; exit 2and <brb>fi<brcode><brspan style="color:#3366CC;font-size:1.2em;">set $(sed 'sifconfig</ span></+code></g' $inputFileb> commands (with appropriate titles) # temporarily convert spaces . Remember to redirect that output to add to + for storing lines the bottom of the file!</li><li>Save, run and confirm that the shell script is working correctly.</li><li>What would be the use of keeping this shell script as positional parametersa Linux system administrator?</li><br/ol><brol><li value="14">Here are some more "complex" Bash Shell scripts, that perform the same task. Although you are not require to understand some of these other tricks, it is recommended that you view the contents of the scripts and save them for xfuture consideration or exmaples.</li><li>The <b><code>wget</code></b> command can be used to quickly download files from the Internet. Issue the following command:<br>do<brb><code>&nbsp<span style="pointer-events: none; &nbspcursor: default; useradd color:#3366CC;font-m -c "$(echo $x | cut -dsize:1.2em;">wget https:" //scs.senecac.on.ca/~murray.saul/text-f2 | sed 'sreport.bash</span></+code></ b></gli><li>Verify that the file ')" ''text-p $(date | md5sum | cut -dreport.bash''' was downloaded to your current directory.</li><li>Assign read and execute permissions for this file by issuing the command: <b><code><span style=" " -f1) $(echo $x | cut color:#3366CC;font-d"size:1.2em;" >chmod u+rx text-f1)report.bash</span></code></b></li><li>Run this Bash Shell script by issuing the command: <b><brcode>&nbsp<span style="color:#3366CC; &nbspfont-size:1.2em; mail -s "Server Account Information" $(echo $x | cut >./text-d":" report.bash</span></code></b></li><li>Check to see if it created a report in your current directory. What is the purpose of the report?</li><li>Use the <b>vi</b> text editor to view the contents of the file <b>text-f3) report.bash</b>. Can you understand how this script works?<+br><br>&nbsp</li><li>Use the <b><code>wget</code></b> command to download, study, and run the following shell scripts on-line:<blockquote><b><code><span style=" pointer-events:none; &nbspcursor:default; Here is your server account informationcolor:<br>&nbsp#3366CC; &nbspfont-size:1.2em; servername">https: myserver//scs.senecac.on.ca/~murray.saul/report.bash<br>&nbsp; &nbsp; usernamehttps: $(echo $x | cut -d":" -f1)//scs.senecac.on.ca/~murray.saul/report3.bash</span><br/code>&nbsp; &nbsp; password: $(date | md5sum | cut -d" " -f1)<br/b>&nbsp; &nbsp; Regards,<br/blockquote>&nbsp; &nbsp; IT Department<br/li>+<brli>doneTry to understand what these Bash Shell scripts do.<br/li><brli>echo You have completed lab1. Proceed to Completing The Lab, and follow the instructions for "lab sign-e "\n\nAccounts have been created\n\noff".<br/li>exit 0<br></codeol>

'''Answer the Investigation 3 observations / questions in your lab log book.'''

= LAB 1 SIGN-OFF (SHOW INSTRUCTOR) =[[Image:lab1_signoff.png|thumb|right|500px|Students should be prepared with a'''ll required commands (system information) displayed in a terminal (or multiple terminals) prior to calling the instructor for signoff'''.]]'''Arrange proof evidence (command output) for each of the following these items on your screen, then ask your instructor to review them and sign off on the screenlab's completion:'''

::<span style="color:green;font-size:1.5em;">&#x2713;</span> Account created on Output of '''centos1lsblk''' VM.command showing correct partition names and sizes::<span style="color:green;font-size:1.5em;">&#x2713;</span> List contents Contents of '''/etc/groupfstab''' file (ops235 group) on confirming partitions file types are '''centos1ext4''' VM.::<span style="color:green;font-size:1.5em;">&#x2713;</span> List contents of Correct '''/etc/passwdIP address''' file (created accounts) on and '''centos1MAC address''' VM::<span style="color:green;font-size:1.5em;">&#x2713;</span> '''Default route (gateway)'''::<span style="color:green;font-size:1.5em;">&#x2713;</span> Display current run-level status on '''centos2DNS name server IP Address''' VM.::<span style="color:green;font-size:1.5em;">&#x2713;</span> Creation Contents of your '''report.bash ''' shell script called ::<span style="color:green;font-size:1.5em;">&#x2713;</span> proof of '''createUsersyum update''' performed on c7host::<span style="color:green;font-size:1.bash5em;">&#x2713;</span> '''lab1 notes''' <u>and</u> '''first column of Comparison Chart in lab2'''.

= Preparing for the Quizzes ADDITIONAL PRACTICE =

# Describe all of the field in <code>'''/etc/passwd'''</code>How many packages were installed?# What is How many files (correct to the command to create a user? What option to create a home directory for that usernearest hundred) were installed?# What is the command to change the full name of an already-How many users were created userautomatically on your system (regular, admin)?# What is the command to delete a user List 3 ways that you can access your root account? What option allows for the user's home directory to be removed as well?# What is the command to create a group? What is difference between the command (or steps) to include a user in a newly-created group?# What is the purpose of <code>commands '''/etc/shadowsu'''</code>?# What is the purpose of <code>and '''/etc/skelsu -'''</code> ?# What does is the term run-level meanhome directory for the user "root"?# How to set do you determine the run-level host name of a your GNU/Linux system to text-based only? How to set to graphical modeworkstation?# What is the command to view can display the status of running servicesNIC's MAC address?# What command is the command used to start get a service (like httpd, or sshd)list of running processes on your newly-installed system?# What is the command to start a servicecopy files to your USB key?# Can How can Shell Scripts be used to help automate a service be stopped and started by issuing just one commandtask performed in lab1?