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OPS245 Lab 3

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{{Admon/caution|DO NOT USE THIS VERSION OF THE COURSE. This page will no longer be updated.|'''Debian version here:''' https://seneca-ictoer.github.io/OPS245

'''CentOS version here:''' https://seneca-ictoer.github.io/OPS245-C7 '''Andrew's version here:''' http://wiki.littlesvr.ca/wiki/OPS245_Lab_3}}

= LAB PREPARATION =

{| width="40%" align="right" cellpadding="10"

#Select Open Virtual Machine, and select the VM called c7host on your Solid State Drive.

#Launch your '''c7host''' machine, and login as as a regular user.

#Boot-up your '''centos1''' VM. '''~~when~~ When the Grub Boot menu appears''', press the letter <code>e</code> (for "edit").

#Using your arrow keys, scroll to next screen to '''linux''', or '''linux16''', or '''linux-efi''' command and type the word <code>single</code> as an argument after '''quiet''' (see diagram for reference) and then press <code>ctrl-x</code> to boot.

#The system should boot into text-based mode. Enter your '''root''' password.

[[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]]

|}

===Part 3: Resetting Forgotten Root Password===

#The system should boot into text-based mode without prompting for root's password.

#Issue the command: <code>chroot /sysroot</code>

#Issue the command: <code>passwd root</code> in order to change your root password (press '''ctrl-c''' if you wish to abort - i.e. not change password). '''NOTE:''' if you are using SELinux in '''enforcing''' or '''permissive''' mode, you will also need to issue the command: '''touch /.autorelabel''' This may take some time depending on the amount of files you have on the file system (usually about 2 minutes).

#To restart in graphical mode, simply enter the command <code>exit</code>, then <code>reboot</code>.

# Issue the command: <code>which lbreakout2</code> Is there a program called '''lbreakout2''' on your system?

# Perform an Internet search for the pattern: <code>lbreakout2 tar.gz</code>

# Go to an appropriate webpage and download a "zipped tarball" (compressed source code) for the '''lbreakout2''' game (filename should be something like: '''lbreakout2-2.6.5.tar.gz''')

#Change to the directory where you downloaded that file (most likely ''~/Download''s).

# Use the '''tar''' command to decompress the "zipped tarball" called something like (not may be exactly): '''lbreakout2-2.6.5.tar.gz'''.

# Change to the directory that contains that ''lbreakout2'' source code.

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<li value="8">Issue the following command: <code>./configure && make</code> Most likely, you will get an '''ERROR!''' What do you think the error is telling you? </li>

<li>Issue the following command to install the files for application development by issuing the command: <code>sudo yum groupinstall "Development Tools"</code></li>

<li>Issue the command in step 78. You should get another ERROR! What dependency is missing?</li><li>Issue the following command to install the library files for SQL by issuing the command: <code>sudo yum install SDL-devel~~</code> (possibly <code>sudo yum install~~ libpng-devel~~</code> and <code>sudo yum install~~ zlib-devel</code> )</li>

<li>Reissue the <code>./configure && make</code> command. Were you successful?</li>

<li>Run the command <code>lbreakout2</code>. Were you successful?</li>

<li>You need to run a command to make this program available regardless of your current directory (as opposed to running command in the directory that contains the program). ~~Login as root (be sure to be in the same directory as the source code after logging in as root) and~~ So, issue the command:~~ ~~<code>sudo make install</code></li>

<li>Run the command: <code>lbreakout2</code>. Did it work? Issue the command: <code>which lbreakout2</code>. What do you think that the '''make install''' command did?</li>

</ol>

<code>

# Use sed with extended regular expressions to only print those matching report elements

rpm -qi xchat

</code>< Notice that using the '''-i ''' option with '''-q ''' causes rpm to generate more output than we have seen from it so far.</li><li>Pick any five packages and run the <code>rpm -qi</code> command on all five at once. This should produce dozens of lines of output. Consider the output it would generate if we used -a instead of picking just a few packages.~~<li>~~<li>Run <code>rpm -qia</code> now.)</li>

<li>That is way too much output for us to reasonably search through, but we have commands that can filter this down to a much more readable amount.</li>

<li>Try the command: <code>rpm -qia | sed -nre '/^Name[[:space:]]+:/ p' -e '/^Install Date[[:space:]]*:/ p'</code>

Instead of printing every line, this will only display the name and install date of each package.</li>

<li>Try modifying that command to display only the package ~~name~~ Name and License.</li>

</ol>

=INVESTIGATION 4: USING LOGICAL STRUCTURES IN PYTHON=

Now that we have added some powerful logical structures to our python scripts, we can make our scripts much more adaptable. ~~Just like we have done in bash, our~~ Our python scripts can now respond to different situations by executing different code, or repeating the same code several times (e.g. keep asking the user for input until they give us something useful). In this investigation you will write a python script that will prompt a user for a directory to archive, ask them if they want the archive compressed, and (only if they do want compression) what type of compression to apply.

<ol>

<li>Add a third prompt (immediately after the other two prompts and before the tar command), asking the user if they want the archive to be compressed. You'll need an if statement to run your tar command with gzip compression if they answered yes.</li>

<li>Test your script to make sure it works.</li>

<li>Add a fourth prompt asking the user what type of compression they want (present them with gzip, bzip2, and xz xzip as options). Note that this prompt should only be shown if the user opted for compression (if they don't want compression, there is no point asking what type they don't want).</li>

<li>Expand the if statement around your actual tar command to use whichever type of compression the user asked for.</li>

<li>Test your script to make sure it works.</li>

<li>Test your script again, but feed it nonsense data (e.g. answer 'very much so' instead of 'y' or 'n' when prompted about compression).</li>

<li>Add loops around your prompts for whether or not the user wants compression, and the compression type to make the script repeat each prompt until the user gives a response your script can actually use. Don't worry about doing anything with the archive name or path.</li>

<li>Now test your script again, with good data and with nonsense.</li>

<li>When you are confident your script works, you are ready to submit the lab.</li>

# Make certain that your '''c7host''' and '''centos3''' VMs are running.

# Switch to your '''c7host''' machine, open a shell terminal as a regular user, and change to the directory: '''~/bin'''

# Download the Lab 3 check script: <code>wget https://~~ict~~raw.~~senecacollege~~githubusercontent.com/OPS245/labs/main/lab3-check.bash</code>

# Give the '''lab3-check.bash''' file execute permissions (for the file owner).

# Run the shell script with <code>sudo</code>, and if any warnings appear, fix the issues noted by the script and rerun the check until you receive the "Congratulations!" message.

Andrew

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