Changes

<li>Add a mount point '''/var/lib/libvirt/images''' (type yourself, check spelling!) for size '''100GiB''' (file-system type '''ext 4 ''' and device type '''LVM''').</li><li>Recheck each of the created partitions, and make certain that the file-system type is set to '''ext4''' and the Device Type should be '''LVM''', unless the instructions above tell you otherwise.</li>

= INVESTIGATION 3: Using the Shell Scripting to Generate System Information Reports =

{{Admon/note|Bash Shell Scripting Reference Guide:|<br>'''<u>She-bang Line</u>'''<ul><li>Forces shell script to run in a specific Shell</li><li>Must be at beginning of first line (eg. '''#!/bin/bash''')<br><br></li></ul>'''<u>Variables</u>'''<blockquote>'''Environment'''<ul><li>System-wide or "global" variable</li><li>Usually appear in UPPERCASE letters</li><li>Can view with command: '''set &#124; more'''</li><li>'''$''' in front to expand variable to value<li>Examples: '''USER''', '''PATH''', '''HOME''', '''SHELL'''</li></ul></blockquote><blockquote>'''User-defined''' <ul><li>Variable created by user (command line, scripting)</li><li>Examples:<br>''myVar&#61;"my value"; readonly myVar; export myVar''<br>''read -p "enter value: " myVar''</li></ul></blockquote><blockquote>'''Positional parameters'''<ul><li>Assign values with set command or shell script arguments</li><li>These variables are numbered (eg. $1, $2 ... $10}</li><li>Special parameters: $*, $@, $#, $$, $?<br></li></ul></blockquote>'''<u>Command Substitution</u>'''<ul><li>Useful method to expand output from a command to be used as an argument for another command.</li><li>Examples:<br>''file $(ls)''<br>''set $(ls);echo $#;echo $*''<br>''echo "hostname: $(hostname)"''<br><br></li></ul>'''<u>if / elif / else statements</u>'''<ul><li>If a command runs (even pipeline command like to grep to match) will be true (0); otherwise, false (non-zero), thus can use with logic statements.</li>Example:<br>''if echo $myVar &#124; grep "match"''<br>''then''<br>''echo "Match"''<br>''fi''<br></li><li>The '''test''' command is used to test conditions. Square brackets '''[ ]''' is short-cut for test command (args contained inside with spaces). The '''exit''' command can be used to terminate the shell script with a false value.<br>Example:<br>''if [ $USER &#61; "root" ]''<br>''then''<br>&nbsp;''echo "You must be root" ''<br>&nbsp;''exit1''<br>''fi''<br></li><li>For numberic comparison, use the '''test options''': '''-gt''','''-ge''', '''-lt''', '''-le''', '''-eq''', '''-ne'''<br>Example:<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></li><li>For testing for file information, you can use '''-d''' to test if directory pathname exists, and '''-f''' if the file pathname exists. You can use '''!''' for negation.<br>Examples:<br>''if [ -d directory-pathname ]''<br>''then''<br> ''echo "directory exists"''<br>''fi''<br><br>''if [ ! - f file-pathname ]''<br>''then''<br> ''echo "File does not exist"''<br>''fi''</li></ul>}}

:You may have learned about creating and running Bash Shell Scripts in your ULI101 course. Shell scripts help Linux users and system administrators to automate repetitive tasks to become more efficient and to help them save time. In order to avoid confusion with syntax, you will not be writing bash scripts in this course. You will be reviewing and building a basic Bash Shell script however still run bash commands to perform various tasks, e.g. to generate information reports for your newly-installed Linux host machine.

<ol><li value="4">Refer to the Bash Shell Scripting Reference Guide prior to proceeding with this section. As you continue, you are required to make Bash Shell scripting notes in your lab1 logbook.</li>

<li value="7">Launch a text editor (such as <b><code><span style="color:#3366CC;font-size:1.2em;">vim</span></code></b> or <b><code><span style="color:#3366CC;font-size:1.2em;">nano</span></code></b>) Using output redirection, send the output from each of the following commands to create a Bash Shell script file called: <b><code><span style="color:#3366CC;font-size:1report.2em;">myreporttxt.bash</span></code></b> in your current directory.</li><li>Copy and paste the text below into your vi editing session for your file report.bash<br> (how do Note that when you copy and paste efficiently in Linux?)<br></li></ol> <code style="color:#3366CC;font-family:courier;font-size:.9em;margin-left:20px;font-weight:bold;"><br>&#35;!/bin/bash<br><br>&#35; Author: *** INSERT YOUR NAME ***<br>&#35; Date: *** CURRENT DATE ***<br>&#35;<br>&#35; Purpose: Creates system info report<br>&#35;<br>&#35; USAGE: ./myreport.bash<br><br>if [ $(whoami) != "root" ] # if not 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="9">Save your editing sessionare done, assign the '''myreport.bash''' you should have one 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 work?</li><li>Run it again with <b><code><span style="color:#3366CC;font-size:1.2em;">sudo ./myreport.bash</span></code></b></li><li>Reopen your text-editing session for '''~/bin/myreport.bash''' and add the following lines that has output from all of code to the bottom of the shell script file:</ol><br><code style="color:#3366CC;font-family:courier;font-size:commands.9em;font-weight:bold;">&#35; Create report title<brul><br>echo "SYSTEM REPORT" li> /root/report.txt<br>echo "Date: $(date +'%A %B %d, %Y (%I:%M %p)')" >> /root/report.txt<br>echo >> /root/report.txt<br></code><brli><ol><li value="13">Save and run the bash shell script (remember to use sudo to run it as root). 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, and then the other redirection symbol &gt;&gt; is used to help "grow" the report with the other content.hostname</li><li>The only remaining content of the report would be the system information. We can use a shell scripting trick called "command substitution" $( .. ) in order place results from an command to be used by another command (like echo). Reuname -edit the shell script and add the following code at the bottom of the shell script file:rv</li></ol><brli>ps aux<code style="color:#3366CC;font-family:courier;font-size:.9em;font-weight:bold;">echo "Hostname: $(hostname)" >> /root/report.txt<brli>echo >> /root/report.txt<brli>echo "Kernel Version: $(uname -rv)" >> /root/report.txtip address show<br>echo >> /root/report.txt<brli></codeul><br/li><ol><li value="15">Save, run the script, and view 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="color:#3366CC;font-size:1.2em;">ps aux</span></code></b> and <b><code><span style="color:#3366CC;font-size:1.2em;">ip address show</span></code></b> commands (with appropriate titles). Remember You should be able to redirect understand them because you just put that output to add to the bottom of the file!</li><li>Savecontent there, run and confirm that the shell script is working correctly.</li><li>What but what would be the use of keeping this shell script as a Linux system administrator?</li></ol><ol><li value="19">Here are some more "complex" Bash Shell scripts, that perform the same task. Although look like if you are not required to understand some of these other tricks, it is recommended that you view look at the contents of the scripts and save them for future consideration or examples.</li><li>The <b><code>wget</code></b> command can be used to quickly download files file several months from the Internet. Issue the following command:<br><b><code><span now? style="pointer-events: none;cursor: default;color:#3366CC;font-size:1.2em;">wget https://ict.senecacollege.ca/~ops245/labs/text-report.bash</span></code></b></li><li>Verify that the file '''text-report.bash''' was downloaded In order to your current directory.</li><li>Assign read and execute permissions for make this file by issuing more readable, use the command: <b><code><span style="color:#3366CC;font-size:1.2em;">chmod u+rx text-report.bash</span></code></b></li><li>Run this Bash Shell script by issuing the command: <b><code><span style="color:#3366CC;font-size:1.2em;">./text-report.bash</span></code></b></li><li>Check line to see if it created add a report in your current directory. What is blank line between the purpose of the report?</li><li>Use the <b>vi</b> text editor to view the contents of the file <b>text-report.bash</b>. Can you understand how this script works?<br><br></li><li>Use the <b><code>wget</code></b> output from each command to download, study, and run a header before each command briefly describing what the following shell scripts onoutput is (note that this will likely require re-line:<br><b><code><span style=" pointer-events:none;cursor:default;color:#3366CC;font-size:1.2em;">https://ict.senecacollege.ca/~ops245/labs/report.bash<br>&nbsp;https://ict.senecacollege.ca/~ops245/labs/report3.bash</span></code></b><br><br></li><li>Try to understand what running all of these Bash Shell scripts docommands).</li></ol>

Before we can successfully automate parts of configuration using python, we need to learn how to use it. Initially we will duplicate perform simple tasks we have already learned how to do in bash. This way can learn how the language works as we go.

In this investigation you will write a python script that duplicates (as closely as possible with the parts of python we have covered so far) the bash script from file we created in the previous investigation.

<li>Populate the beginning of the file with sh-bang line and block comment equivalent to describing what was in '''myreport.bash'''this script does:

<li>You'll notice that the python script is currently sending its output to your terminal. Since we haven't covered how to write to a file yet, this is ok for now. Just use output redirection on the command line when you run the script to send the output to '''~/bin/pythonreport.txt'''.</li>

<li>Run your script to make sure it works. Note that the output does not need to match the bash script investigation 3 exactly, but it should be very close.</li>

# Write a Bash Python Shell Script to prompt the user for a directory, and then display the file types for all files in that specified directory (hint: use the '''read''' command and then use the '''file''' command and '''command substitution''' with the '''ls''' command). Test the Bash Shell script by adding execute permissions and run the Bash Shell Script.# Modify the previously created shell script to perform error checking after prompting for a directory to test if the specified directory does not exist. If it does NOT exist (i.e. true), display an error message indicating that the directory does NOT exist, and issue the command exit 1 to terminate the Bash Shell Script. Test the Bash Shell script by adding execute permissions and run the Bash Shell Script.