Changes

[[Category:OPS235]][[Category:OPS235 Labs]]{{Admon/caution|THIS IS AN OLD VERSION OF THE LAB|'''This is an archived version. Do not use this in your OPS235 course.'''}}= LAB PREPARATION =

==IntroductionPurpose / Objectives of Lab3==[[Image:software.png|thumb|right|300px|Installing software is an important task for computer system administrators. ]]

In this lab , you're are going to:identify potential problems such as not properly compressing VM image files when backing up VMs, or forgetting your root password. You will also learn to conserve hard disk space by learning how to compress and decompress files that are stored on your computer server. In addition, you will learn alternative methods of how to install applications (i.e. programs).

== Required Materials *Learn to troubleshoot some common problems after installing VMs*Create and extract '''archive''' files (tar and tar.gz)*Install applications using various methods::*'''Download''', '''decompress''' and archive file from the Internet, then '''compile source code''' in order to install an application.:*Use '''yum''' utility to install software from '''local source programs''' (on DVD drive):*Use '''yum''' utility to install software from '''repositories''' (Bring online storage areas):*Learn how to All Labs'''add repositories''' (online software storage areas) to install less common applications.<ul><li value=="4">Demonstrate the use of Bash Shell scripts to automate routine tasks (generate a customized software report)</li></ul>

==PrerequisitesMinimum Required Materials==

* Completion and Instructor {|cellpadding="Sign15" width="40%" |-offvalign="top" |width="10%" of Lab 2| [[Image: blank-cd.png|thumb|left|85px|<b>CentOS7</b><br>FULL DVD]] |width="10%" | [[OPS235 Lab 2 Image:harddrive.png|thumb|left|85px|<b>Removable Hard Disk Pack</b> (SATA)]] |width="10%" |[[Image:ubs- CentOS6key.png|thumb|left|85px|<b>USB key</b><br>(for backups)]] |width="10%" |[[Image:log-book.png|thumb|left|70px|<b>Lab3 Log Book</b>]] |} ==My Toolkit (CLI Reference)== {|width="100%" cellpadding="15"|- valign="top"|width="10%" |<u>Archiving / Compiling:</u>[http://man7.org/linux/man-pages/man1/tar.1.html tar]<br>[http://unixhelp.ed.ac.uk/CGI/man-cgi?gzip gzip, gunzip]<br>[http://man7.org/linux/man-pages/man1/make.1.html make]|width="10%" |<u>Software Manangement:</u>[http://www.rpm.org/max-rpm/rpm.8.html rpm]<br>[http://man7.org/linux/man-pages/man8/yum.8.html yum]|width="10%" |<u>Commands</u>[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/wget.1.html wget]<br>[http://man7.org/linux/man-pages/man1/chmod.1.html chmod]<br>[http://ss64.com/vi.html vi] |width="40%" |{{Admon/tip|Online Linux Command Review|The following tutorial will allow you to learn essential shell scripting skills:<ul><li>Shell Scripting Basics - Part 4 (The sed Utility):<br>'''/home/murray.saul/scripting-4'''</li></ul>|}}|}

= INVESTIGATION 1: TROUBLESHOOTING AFTER VM INSTALLS & BACKUPS ={|width="10050%" align="right" cellpadding="510"|'''LVM Information Utilities:'''|'''LVM Management Utilities:'''|'''Additional Utilities:'''

*[http://linuxmanpages.com/man8/vgs.8.php vgs]*[httpImage://linuxmanpagesgrub1.com/man8/lvs.8.php lvs]*[http://linuxmanpages.com/man8/pvs.8.php pvs]*[http://linuxmanpages.com/man8/vgdisplay.8.php vgdisplay]*[http://linuxmanpages.com/man8/lvdisplay.8.php lvdisplay]*[http://linuxmanpages.com/man8/pvdisplay.8.php pvdisplay]png|thumb|right|*[http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-system-config-lvm.html system-config-lvm] (Tutorial)*[http://linuxmanpages.com/man8/lvextend.8.php lvextend]*[http://linuxmanpages.com/man8/resize2fs.8.php resize2fs]*[http://linuxmanpages.com/man8/lvcreate.8.php lvcreate]*[http://linuxmanpages.com/man8/lvreduce.8.php lvreduce]*[http://linuxmanpages.com/man8/pvcreate.8.php pvcreate]*[http://linuxmanpages.com/man8/vgextend.8.php vgextend]600px|*[http://linuxmanpages.com/man8/mount.8.php mount]*[http://linuxmanpages.com/man8/umount.8.php umount]*[http://linuxmanpages.com/man8/yum.8.php yumPress '''e''' at Grub Boot Menu to edit]*[http://linuxmanpages.com/man8/rpm.8.php rpm]

==Resources on the web==Additional links to tutorials and HOWTOs:'''Please read this page to get an overview Troubleshooting consists of LVM3 basic elements:'''<br /><br />:* [[Logical Volume Management]] ('''Note:''' It is recommended to return to this guide as a reference when performing the next several investigations):* [http://fedoranews.org/alex/tutorial/rpm/ Using the RPM Utility]:* [http://www.centos.org/docs/5/html/yum/ Using the YUM Utility]

== Check Current LVM Information Prior If you cannot log graphically into your machine (first 3 common problems), there is a trick to Performing Investigations ==boot your system into '''single-user''' mode. This mode does not provide networking, graphics, or logging in as other regular users, but can connect to a text-based interface as the '''root''' user. This method will only work if a GRUB (<u>'''Gr'''</u>and '''<u>U</u>'''nified <u>'''B'''</u>oot-loader) password has not been set, or that you haven't forgotten the GRUB password.

'''Although the concept of LVM is simple, it takes practice and preparation (or Steps to Boot into "thinking aheadSingle-User Mode") in order to correctly use this valuable tool:'''. It is important for students to gain an understanding of LVM, and how to manage their filesystems using LVM. It is recommended for students to read the following resource prior to this lab and/or return to the following resource while performing this lab: [[Logical Volume Management]]

At this point, having completed {| width="50%" align="right" cellpadding="10"|- valign="top"|[[OPS235 Lab 2 Image:grub2_1.png|thumb|right|600px|Add the boot option '''single''' and then press '''ctrl- CentOS6|Lab 2x''' to boot into single user mode]] |}#Boot-up your '''centos1''' VM. '''when the Grub Boot menu appears''', press the letter <b><code><span style="color:#3366CC;font-size:1.2em;">e</span></code></b> (for "edit").#Using your arrow keys, scroll to next screen to '''linux''' or '''linux-efi''' command and type the word <b><code><span style="color:#3366CC;font-size:1.2em;">single</span></code></b> as an argument after '''quiet''' (see diagram for reference) and then press <b><code><span style="color:#3366CC;font-size:1.2em;">ctrl-x</span></code></b> to boot.#The system should boot into text-based mode. Enter your '''root''' password.#One thing to look at is partition space usage. Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">df -h</span></code></b>#If you should have roughly notice 0% free space in the '''/''' partition, then there is a problem. This most likely is caused by not following disk storage setupsteps to create a <u>compressed</u> copy of the VM image. If that is the case, locate the large image backup and remove it. Do NOT remove the image in ''/var/lib/libvirt/images'' directory!#You can use the '''passwd''' command to reset your '''regular user''' password (eg. <b><code><span style="color:#3366CC;font-size:1.2em;">passwd regularuserid</span></code></b>). You can press '''ctrl-c''' if you wish to abort (i.e. not change password).#To restart in graphical mode, simply enter the command <b><code><span style="color:#3366CC;font-size:1.2em;">reboot</span></code></b>.

('''Note:''' These results are output from the '''vgs'''Unfortunately, this method does not work if you forgot your '''pvsroot'''password (To reset your root password, and '''lvs''' commands that provide volume group, physical volume and logical volume information for each of the virtual machines that you created in lab2. Before proceeding, check these values with your own system refer to see if you are generally "on the right track"procedure below).)

PV VG Fmt {| width="50%" align="right" cellpadding="10"|- valign="top"|[[Image:grub2_3.png|thumb|right|600px|Add '''rw init=/sysroot/bin/sh''' as shown and then press '''ctrl-x''' to boot into single user no root password mode]]|}#The procedure to reset root's password is different than shown above. Press <b><code><span style="color:#3366CC;font-size:1.2em;">e</span></code></b> at the Grub boot menu.#Using your arrow keys, move to '''linux''' Attr PSize PFreeor '''linux-efi''' command and replace the argument '''ro''' with the argument <b><code><span style="color:#3366CC;font-size:1.2em;">rw init=/sysroot/bin/sh</span></code></b> (see diagram for reference) and then press <b><code><span style="color:#3366CC;font-size:1.2em;">ctrl-x</span></code></b> to boot.#The system should boot into text-based mode without prompting for root's password.#Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">chroot /sysroot</span></code></b><br><br> #Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">passwd root</span></devcode></vda3 vg_centos1 lvm2 ab> in order to change your root password (press '''ctrl-c''' if you wish to abort - 9i.e. not change password).#To restart in graphical mode, simply enter the command <b><code><span style="color:#3366CC;font-size:1.2em;">reboot</span></code></b>.50g 0

* '''centos2Catastrophic Boot Problems:'''

VG #PV #LV #SN Attr VSize VFree vg_centos2 1 3 0 wz:Not being able to start your '''c7host''' due to '''Kernel Panic''' or some sort of '''catastrophic disk failure''' is not as easy to fix. You might be able to boot from your '''Centos LIVE DVD, open a terminal and mount the partition''' via command line and look for possible problems (setup files like '''/etc/fstab'''). '''Lab5''' will discuss more about mounting and the /etc/fstab file. The "worst-case scenario" would be to purchase a new hard disk, '''perform lab1 completely, perform lab2 to install and set-n- 19up virtualization software''', then '''restore your VM image and xml file backups''' (eg. decompressing images, issuing virsh define commands for .51g 7xml files).77gThat is why consistently '''performing backups of ALL of your VMS at the end of each lab is absolutely essential! You have been warned!'''

LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert lv_home vg_centos2 -wi-ao---- ==Part 1.95g lv_root vg_centos2 -wi-ao---- 7.81g lv_swap vg_centos2 -wi-ao---- 1.97g : Creating a File Archive==

#Boot up your '''centos3''' VM.#Change your working directory to '''/usr/share/doc/sudo* '''centos3 #Use the tar (Note: This VM has no GUI installedtape archiver)command to create an archive file named '''/tmp/archive1.tar''' VG #PV *<b><code><span style="color:#LV #SN Attr VSize VFree vg_centos3 3366CC;font-size:1 3 0 wz--n- 14.51g 42em;">tar cvf /tmp/archive1.tar .54g</span></code></b>

PV VG Fmt Attr PSize PFree{| width="40%" align="right" cellpadding="10" |- valign="top"|colspan="2"|{{Admon/devimportant | Warning! | Don't miss the '''.''' at the end of the <code>tar</vda3 vg_centos3 lvm2 a-- 14.51g 4code> commands below! It specifies what should go into the archive: the contents of the current directory.54g}}

|}<ol> LV VG Attr <li value="4">What do the options '''c''', '''v''', and '''f''' mean?</li> LSize <li>Record the archive file size.</li> Origin Snap% Move Log Copy% Convert<li>Compress the file using '''gzip''': lv_home vg_centos3 -wi-ao--- <ul> <li><b><code><span style="color:#3366CC;font- size:1.00g 2em;">gzip /tmp/archive1.tar</span></code></b></li> </ul> lv_root vg_centos3 -wi-ao---- </li> 8<li>Record the archive file size after compression.00g </li> lv_swap vg_centos3 <li>Make sure you're still in '''/usr/share/doc/sudo*''' and then create a compressed archive:<ul> <li><b><code><span style="color:#3366CC;font-wi-ao---- 992size:1.2em;">tar cvzf /tmp/archive2.tgz .00m </span></code></b></li> </ul>* </li> <li>What does the''' z''' option do?</li> <li>Compare the sizes of '''c6host (i/tmp/archive1.etar. "removable hard disk" or "disk pack")gz''' and '''/tmp/archive2.tgz'''. Why are they so close in size?</li></ol>

Does not use LVM. Confirm this using '''Answer the same commands used abovePart 1 observations / questions in your lab log book.'''

{{Admon/note|VM Backups and Recovery|Most of these investigations will take place ===Part 2: Restoring Files From an Archive===#Remain in your virtual machines'''centos3''' VM. If you make a significant mistake, #Create the directory '''/tmp/extract1'''#Change to the '''/tmp/extract1''' directory.#Move the file '''archive1.tar.gz''' to your virtual machine may not bootcurrent directory. Remember that #Unzip the first archive you created backups of your virtual machines in Lab 2, and you can restore them if something goes wrong:#*<b><code><span style="color:#3366CC;font-size:1.2em;">gunzip archive1.tar.gz</span></code></b>#Extract the files from the first archive:#*<b><code><span style="color:#3366CC;font-size:1.2em;">tar xvf archive1.tar</span><br /code><br /b>#Are all the files there? #Compare '''/tmp/extract1/README''' and '''Remember/usr/share/doc/sudo*/README'''. Are they exactly the same? Why?#Create the directory '''/tmp/extract2'''#Move the file '''archive2.tgz''' to the '''/tmp/extract2''' directory.#Extract the files from the second archive:#*<b><code><span style="color:#3366CC;font-size: if you did 1.2em;">tar xvzf /tmp/extract2/archive2.tgz</span></code></b>#Note that this time a separate <b><code><span style="color:#3366CC;font-size:1.2em;">gunzip</span></code></b> command was not create backups for all of your VMsneeded. Why?#Repeat the previous command, then you donleaving out the option '''z'''. Does it work? Why?#Compare the '''t have any restoration points to fall-back to!README'''|}}file in this directory with the original file. Are they exactly the same?

Let's say that you have run out of disk space on your computer (centos3)===Part 3: Practical Application - Compiling Source Code from Archive File==={| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/note|Installing Development Libraries|In the future, remember the above procedure whenever installing software from source. Sometimes, you need more space on the root filesystem, perhaps to host more webpages install additional tools or libraries in order to compile a larger database or new particular software. What are your options? Getting a replacement harddrive would probably require reinstallation of the operating system and backup/restore of the data.package}}

Because |}Now that you know how to create and decompress "zipped tarball archives", we're using LVM though will demonstrate how to install applications from websites containing these types of archives. Although this method is not as "user- we can avoid that. We can add a new harddrive (which will serve friendly" as a physical volume) to using the volume groupyum or rpm command, and extend this method is useful if the root logical volume to make use of the new available spaceapplication is NOT contained in regular software repositories...

'''Perform In order to build software from source code, you must have the following operations to increase appropriate software development tools (such as make and gcc) and libraries (such as GTK) installed. The required tools will vary depending on the size of lv_root computer languages used in centos3:'''the software being built.

<u># Part is to be performed in your '''centos2'''VM.# Issue the following command to install a basic set of development tools and libraries:<br /><b><code><span style="color:#3366CC;font-size:1.2em;">yum groupinstall "Development Tools" "Development Libraries"</span>Steps:</fontcode>'''</ub><br><br>

<li value="3">Go to the directory '''/tmp'''</li> <li>Use the <b><code><span style="color:#3366CC;font-size:1.2em;">wget</span></code></b> command to download the "tar ball" that contains the source code for the NLED text editor. <code>wget</code> is a command-line tool to download files from the web using the http or ftp protocols. <ul> <li><b><code><span style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">wget http://cdot.senecac.on.ca/software/nled/nled_2_52_src.tgz</span></code></b></li> </ul> </li>Run <li>Extract the following commands and make note of files. Change to the outputnewly-extracted directory (<b><code><span style="color:#3366CC;font-size:1.2em;">/tmp/nled-2.52</span></code></b>)</li> <li>Check to see if there is a file named <b><code><span style="color:#3366CC;font-size:1.2em;">configure</span></code>ls </devb>. If so, run it; if not, skip this step. (Most but not all source code archives contain this file)</vd*li> pvs<li>Check to see if there is a file named <b><code><span style="color:#3366CC;font-size:1.2em;">Makefile</span></code></b> or <b><code><span style="color:#3366CC;font-size:1.2em;">makefile</span></code></b>. If so, type the command: <ul> <li><b><code><span style="color:#3366CC;font-size:1.2em;">make</span></code></b></li> vgs <li>Did the command work? Why? Use the <b><code><span style="color:#3366CC;font-size:1.2em;">yum</span></code></b> command to install the package '''gcc'''. What do you think the package ''gcc'' does?</li> lvs </ul> df <li>Reissue the <b><code><span style="color:#3366CC;font-hsize:1.2em;">make</span></code></b> command. Where you successful? What does <code>make</code> do?</li> <li>Open Issue the command as root: <b><code><span style="color:#3366CC;font-size:1.2em;">yum list ncurses</span></code></b>. What do you see? Issue the centos3 virtual machine consolecommand at root: <b><code><span style="color:#3366CC;font-size:1.2em;">yum search ncurses</span></code></b>. What do you observe?</li> <li>Go In this case, you need to install the ncurses development libraries as well. Issue the following command as root: <b><code><span style="color:#3366CC;font-size:1.2em;">yum install ncurses-devel.x86_64</span></code></b>. Now issue the hardware details viewcommand: <b><code><span style="color:#3366CC;font-size:1.2em;">make</span></code></b></li> <li>Some software distributed as source code can automatically install itself. Try this command: <ul> <li>Click <b><code><span style="Add Hardwarecolor:#3366CC;font-size:1.2em;" and add a new storage device >make install</span></code></b></li> </ul> </li> <li>Most but not all source code archives include the capability of 2GBsinstalling themselves this way.</li> <li>If the command <code>make install</code> does not work (how can you tell? What command did you learn from ULI101 to confirm that this command cannot be run from the command line?), make sure it's a VirtIO diskcopy the <b><code><span style="color:#3366CC;font-size:1.2em;">nled</span></code></b> program manually: <ul> <li><b><code><span style="color:#3366CC;font-size:1.2em;">cp nled /usr/local/bin</span></code></b></li> </ul> </li> <li>Go back Run <b><code><span style="color:#3366CC;font-size:1.2em;">nled</span></code></b> from the current directory to make sure that it works. To exit this application, press '''ESC''', then type the console viewletter '''q''' at the command prompt as the bottom left-hand corner and then press '''ENTER'''.</li> <li>Run Why did copying the nled executable to '''/usr/local/bin''' allow the same ls nled command (performed to be run by name anywhere in step 1), what's changedthe command prompt?</li> <li/ol>Now we '''Answer Part 3 observations / questions in your lab log book.'''ll make  =INVESTIGATION 3: Using the new device as Yum Command for Local & Repository Installs=  == Manage Software and Repositories with Yum ==  {| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/note|Internet Connection|In order for yum to work you require a physical volume, add it connection to the Internet. Establish this connection by using the browser to log into SeneNET}} |}#Perform this section in your '''c7host''' machine.#Issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">yum install elinks</span></code></b>#Now issue the volume group, and extend lv_rootcommand: <b><code><span style="color:#3366CC;font-size:1.2em;">yum info elinks</lispan></code></b> #How can you tell if the elinks package has been installed?#To remove the elinks package issue the command: <b><code><span style="color:#3366CC;font-size:1.2em;">yum remove elinks</span></code>pvcreate </b># Verify that the elinks package has been removed. Also verify that the application called: '''xchat''' is not installed.# Place your Centos7 Full Install DVD into the DVD drive of your hostmachine.# View the contents of the DVD drive using the file manager application (called '''nautilus'''). Change to the Packages subdirectory. What does this subdirectory contain?# Use a graphical file manager to view the contents of the DVD in your machine.<br><br>'''TIP:''' If you are having problems locating pathname to your DVD, open a terminal, login as '''root''', issue the command: '''mount''', and look for a path-name containing your Centos Install DVD and use that path-name when required later in this section.<br><br># Open a shell terminal and use the Linux command '''cd''' to change to the '''Packages''' sub-directory (hint: similar path-name as USB, but use '''Centos 7 x86_64/devPackages''' and use '''quotes''' " " around full path-name since there are spaces within the pathname). {| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/vdbnote|A Note about Repositories|Since software repositories are on-line storage areas for software for particular Linux distributions, the Linux administrator can enable (add) or disable (remove) additional software repositories. Usually only the basic or "base" repositories are enabled upon Linux installation.}}|}

::* '''Answer yum localinstall''' (install rpm files located from the Investigation 4 observations / questions in your lab log book.machine via downloads to hard-drive, DVD, etc)::* '''yum install'''(install applications from an online repository)

'''Perform this investigation on the VM named '' <uol>centos2 </uli value="11">Within the '''.Packages'''[[Image:Ops235_lab4_1.png|thumb|right|Screenshot subdirectory of system-config-lvm in CentOS. Click to enlarge.]]# Letthe 's learn to administer (manage) our LVM graphically for our ''Centos7 Full Install DVD'centos2''' Virtual Machine.<br />CentOS provides a tool called <code>system-config-lvm</code> to graphically administer LVM. The package is not installed by default, so you will need to install it by issuing: (<code>yum install system-config-lvm</code>).<ol> <li value="2">Use this tool to determine the current LVM configuration by clicking on the appropriate element and reading the properties in the right-hand panel -- write down the answers: <ol type="a"> <li>What are the names and sizes of locate the '''PVrpm'''s?</li> <li>What is the name and size of file that contains the '''VGxchat'''?</li> <li>application (note the full path-name of the file). What are do you think is the names and sizes purpose of the '''LV'''s?</li> <li>Is there any space numbers also contained in the VG which is not allocated to a LVfilename?</li> </olli>Issue the command: </lib> <licode>Increase the size of the home file-system to '''4 GB''': <ol typespan style="acolor:#3366CC;font-size:1.2em;"> yum localinstall "full_pathname_to_xchat_rpm_file"<li/span>Click on the LV containing the '''home''' filesystem.</licode> <li/b>Click on ''Edit Properties''.</li> <li>Change Verify that the size to '''4 GBxchat''' and click ''Ok''command has been installed.</li> </ol> <li>Create a '''new 3G LV''' (LV Properties: linear) containing an ext4 filesystem named lv_archive and mount it at '''/archive''' <li>Backup <code>'''/etc'''</code> into <code>'''/archive'''</code></li>

 {| width="40%" align="right" cellpadding="10"|- valign="top"|colspan="2"|{{Admon/tip|IRCs:A Great Tool for Linux Administrators|Although Search Engines (like Google) are a system administrator's good friend, Internet Relay Chats (IRCs) are also a great tool for system administrators to help obtain information. Many website offer information on how to connect to IRCs (both nodes (eg. FreeNode) and irc channel (eg. #linux).<br><br><u>'''A few tips to consider with IRCs'''</u>:* Copy the files in <ul><li>Do your Homework (read docs first!)</etc into the filesystem mounted at li><codeli>Ask specific questions</archiveli><li>Not all chats are friendly</codeli><br li>Be patient when asking questions (use courtesy)</li><li>The advise is free (use the graphical tools or the command line. If using cp, remember to use the -R optionyou get what you pay for!).</ul>}}|} 

<li value="614">Shrink We will now look at how we can add different repositories to our '''c7host''' machine.</li><li>As root, issue the following command: <b><code><span style="color:#3366CC;font-size of :1.3em;">yum repolist</span></code>lv_archive</codeb></li><li> Take a few moments to view the contents of the file. Do you see which repositories are used by the '''1 GByum'''command? Write down the repositories in your lab logbook.</li><li>View the following link to see a general listing of repositories:<br>[ [http://wiki.centos.org/AdditionalResources/Repositories Available Repositories for Centos] ].</li><li>To add this repository, issue the command:<br><b><code><span style="color:#3366CC;font-size:1.3em;">wget https://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-6.noarch.rpm</span></code> </b><br>Or if you receive a error message, try the command: <br><b><code><span style="color:#3366CC;font-size:1.3em;">yum install epel-release</span></code> </b></li><li>To enable the repository in yum, issue the following command:<br><b><code><span style="color:#3366CC;font-size:1.3em;">yum install epel-release-7-6.noarch.rpm</span></code></b></li> <li>Try shrinking To clean-up the repository list (including downloading new applications in added repositories), issue the home filecommand: <b><code><span style="color:#3366CC;font-size:1.3em;">yum clean all</span></code></b></li><li>To verify that you have added the repository, you can issue the command: <b><code><span style="color:#3366CC;font-size:1.3em;">yum repolist</span></code></b></li><li>Unused and unneeded software can present a security risk and ties up disk space needlessly. Find '''at least 4 other packages''' to remove on your c7host machine(for example: '''sound & video''', '''games''', etc) that you're not using on your system. What happens? Why?Be careful to ensure that removing those packages does not also remove other software that you do need.</li>

'''Answer Investigation 3 observations / questions in your lab log book.''' = Updated backup INVESTIGATION 3: LOOKING AHEAD = ==Automating Routine Tasks (Shell Scripting)=={|width="40%" align="right" cellpadding="10"|- valign="top"|{{Admon/tip|Bash Shell Scripting Tips:|<br><ul><li>'''The Here Document'''<br><br>A neat little trick involving a special type of redirection of stdin ( '''&lt;&lt;''' ) that allows input to be redirected to a command from within the command. '''The name relates to where the stdin is contained: not in a file, but "here in the command itself"'''. A character (like '''+''') is used to mark the boundary of stdin. It is important that the ending boundary only contains a line with that matching character (eg '''+'''); otherwise the stdin will continue to be read! This command is a convenience way to display multiple lines on that screen, but this command can be used with any Linux command that accept stdin.<br><br><u>'''Examples''' (try at the shell prompt)</u><br><br>''cat &lt;&lt;+<br>This is a test message<br>This is the second line<br>+''<br><br>''mail -s "test message" youremailaddr &lt;&lt;+<br>This is a test message<br>I hope you like it.''<br>+<br><br>''tr [a-z] [A-Z] &lt;&lt;+<br>i like ops235<br>i love scripting.<br>+''<br><br></li><li>'''Using sed to Manipulate Text'''<br><br>The Linux command '''sed''' stands for <u>'''S'''</u>treaming <u>'''Ed'''</u>itor which is an effective way to manipulate a text file, output sent from a command, or from within a "here document". This command can manipulate matching text on a variety of criteria (such as line number, regular expression match, etc). Commands can then be used for manipulation such as omitting, printing, substituting, adding, inserting, etc. The sed option -n suppresses display of text so the print (p) command can be used; otherwise, the text will be displayed (with edits via the sed command instructions ). Results of text manipulation with sed can be stored in a variable using command substitution, or redirected to a file. NEVER redirect the stdout from a sed command to the same input file (or the input file will be destroyed)! <br><br></li><li>'''<u>Examples''' (try at the shell prompt)</u><br><br>''sed 's/&#124;/ /g' &lt;&lt;+<br>I&#124;like&#124;weekends!<br>+''<br><br>''sed 's/$/\n/g' &lt;&lt;+<br>This text<br>should be<br>double-spaced!''<br>+<br><br></li></ul>}}|}  We will continue with using shell scripts to create a Software Information Report that manipulates output generated by the '''rpm''' command. The '''sed''' and '''awk''' commands are very useful tools in shell scripting to manipulate text. In this lab, we will be using ''sed'' to allow the user to select certain portions from the rpm command (options -qi). If you require <u>'''additional practice'''</u> in creating shell scripts using the "sed" utility, run the following command in your '''Matrix''' account:<br>'''/home/murray.saul/scripting-4'''<br><br># Perform the following steps in your '''c7host''' machine for this section.# Open a Bash shell terminal and login as root.# Use a text editor (such as <b><code><span style="color:#3366CC;font-size:1.2em;">vi</span></code></b> or <b><code><span style="color:#3366CC;font-size:1.2em;">nano</span></code></b>) to create a Bash Shell script called: <b><code><span style="color:#3366CC;font-size:1.2em;">packageInfo.bash</span></code></b> in root's home directory.# Enter the following text content into your text-editing session:<code style="color:#3366CC;font-family:courier;font-size:.9em;margin-left:20px;"><br>&#35;!/bin/bash <br><br>&#35; packageInfo.bash<br>&#35; Purpose: Generates a report to displaying specified information of installed software<br>&#35;<br>&#35; USAGE: ./packageInfo.bash [application-name]<br>&#35;<br>&#35; Author: *** INSERT YOUR NAME ***<br>&#35; Date: *** CURRENT DATE ***<br><br>if [ $HOME != "/root" ] # only runs if logged in as root<br>then<br>&nbsp;echo "You must be logged in as root." >&2<br>&nbsp;exit 1<br>fi<br></code><br><ol><li value="4">Save your editing session, but remain in the text editor.</li><li>The code displayed below will require the user to include only one argument after the command (script) which will be the application name. The following code will also generate the report title and current date. Add the following code</li></ol><br><code style="color:#3366CC;font-family:courier;font-size:.9em;"> if [ $# -ne 1 ]<br>then<br>&nbsp; echo "Your command must have a application-name as argument" >&2<br>&nbsp; echo "USAGE: $0 [application-name]" >&2<br>&nbsp; exit 1<br>fi<br><br>&#35; Create report title (echo with -e option allows newline \n character to be used)<br>echo -e "\nSOFTWARE PACKAGE INFORMATION REPORT" > /root/package-info.txt <br>echo -e "Date: $(date +'%A %B %d, %Y (%H:%M:%p)')\n\n " >> /root/package-info.txt<br> </code><ol><li value="6">Save your editing session, but remain in the text editor.</li><li>The code displayed below uses a trick called the "Here Document" to redirect stdin from within the command (a quick way to display output on the screen). The read command will store the different information report items as words (separated by a space). The sed command used to convert the spaces to pipes (|) and stored into another variable. This allows the sed command to use extended regular expressions to print rpm elements that match those various patterns to be added to the report. Add the following code</li></ol><br><code style="color:#3366CC;font-family:courier;font-size:.9em;">&#35; Clear screen and use Here Document to display select on report items to read into variable<br>clear<br>cat &lt;&lt;+<br>Available Package Information Items:<br><br>Name<br>Summary<br>Version<br>License<br>Source<br>URL<br>+<br>read -p "Enter word(s) shown above separated by spaces: " choice<br><br>&#35; Convert spaces to pipe symbol (|)<br>processedChoice=$(echo $choice | sed 's/ /|/g')<br><br>&#35; Use sed with extended regular expressions to only print those matching report elements<br>rpm -qi $1 | sed -r -n "/($processedChoice)/ p" &gt;&gt; /root/package-info.txt<br><br>cat &lt;&lt;+<br>File "/root/package-info.txt" has been created<br>+<br></code> <ol><li value="8">Save, set permissions, and then run that shell script for the application '''gedit'''. Did it create that report? Try running the script without an argument - What did it do? <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;cursor:default;color:#3366CC;font-size:1.2em;">https://scs.senecac.on.ca/~murray.saul/packageInfoGraphical.bash</span></code></b></blockquote></li><li>Try to understand what this Bash Shell script does.</li><li>You have completed lab3. Proceed to Completing The Lab, and follow the instructions for "lab sign-off".</li></ol>

If you completed this '''Answer Investigation 3 observations / questions in your lab correctly - please make sure you are still making full backups of your virtual machineslog book.'''

Remember adding = LAB 3 SIGN-OFF (SHOW INSTRUCTOR) ={{Admon/important|Time for a new harddrive to centos3? You will need to back up that drive as well. backup!|If you don't - you will only have half successfully completed this lab, make a new backup of your virtual machines as well as your host machine backed up, which is of no use for a recovery.}}

= Completing '''Arrange proof of the lab =following on the screen:'''

{{Admon<ol><li><span style="color:green;font-size:1.5em;">&#x2713;</span> '''centos3''' VM:<blockquote><ul><li> '''Archived''' files created</li></ul></blockquote></li><li><span style="color:green;font-size:1.5em;">&#x2713;</span> '''c7host''' Machine:<blockquote><ul><li> '''Four unnecessary packages removed'''</li><li> '''xchat''' package installed</important|Time li><li> '''One repository added''' for a new backup!|If you have successfully completed this lab, make a new backup yum</li><li>Creation of your virtual machinesbash shell script called '''packageInfo.}}bash'''</li></ul></blockquote><li><span style="color:green;font-size:1.5em;">&#x2713;</span> '''Lab3''' log-book filled out.</li></ol>

'''Arrange evidence for each of these items on your screen== Practice For Quizzes, then ask your instructor to review them and sign off on the lab's completion:'''# elinks application removed on the host (disk pack - main system c6host).# Unnecessary/unused packages have been deleted (list at least 4Tests, and show that they are no longer installed).# Fresh backup of the virtual machines.Midterm &amp; Final Exam ==

= Preparing #What is the purpose of booting into single-user mode?#List steps in order to boot into single-user mode#What is the difference between a .tgz file and a .tar.gz file? What do these stand for Quizzes =?#What is the purpose of a repository?#What is source code?#How do you build software from source code?#Which is preferred: installing from an RPM file, or installing from source code? Why?#What does yum do that rpm does not?#List the steps to install a package via rpm command.#List the steps to determine detailed information regarding an install package via rpm and yum commands.#List the steps to remove a package via rpm command.#List the steps to install a package using the yum command.#List the steps to remove a package using the yum command.