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Python Reference<br />

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<b><code><span style="color:#3366CC;font-size:1.2em;">%wheel ALL=(ALL) ALL</span></code></b><br />

::This means that anyone who is part of that group can run ''any'' command, as ''any'' user. Effectively, they can use sudo to be root.

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<li>During the lecture, you should have learned some reasons to limit access to the actual root account, and why using sudo is a better practice. Record your observations.</li>

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# Remain in your '''centos1''' VM for this section.

# Issue the following Linux command: <b><code><span style="color:#3366CC;font-size:1.2em;">systemctl get-default</span></code></b><br><br>'''Note:''' The output should read '''graphical.target'''

# You can use the '''systemctl isolate''' command to change the current target. See a list of targets [https://www.centos.org/docs/5/html/5.2/Installation_Guide/s2-init-boot-shutdown-rl.html here].

# Change the current target in '''centos1''' to '''multi-user.target''' by issuing the following command:<br><b><code><span style="color:#3366CC;font-size:1.2em;">sudo systemctl isolate multi-user.target</span></code></b>

<ol><li>You will be using your '''c7host''' machine for this section.</li>

<li>Change to your '''bin''' directory.</li>

You'll notice that even after hitting enter to run the command, you still needed to give more data to your script (to tell it which directory you wanted to archive, what to call it, and what compression to use). <br />

Requiring this much interaction from the user means that this script is not very good for automation. We can't schedule this script to automatically run, because we (or another admin) need to be present to type answers to the prompts.</li>

<li>Import the argparse module into tarchiver2.py.</li>

<li>Add the following lines to your script, after the import, but before you prompt the user for anything:<br />

<code>destination = args.dest</code><br />

Note: Instead of '''destination''', use the variable name were already using to store the value you were getting from the user. That way you won't have to change it in the rest of your script.</li>

If you didn't provide secondtmp.tar on the command line when you ran the command, you'll notice that your script complained. Try running:<br />

<li>You should still be getting prompted about the directory you want to archive, and whether or not you want compression, but you are now telling the script that the created archive should be called secondtmp.tar.</li>

<li>Run the script again, but this time give the archive a different name of your own choice. Your script is part way to being automatable: the user can set the name of the created archive before the script runs. We just need to make this possible for the rest of the required data.</li>

# Make certain that your '''c7host''', '''centos1''' and '''centos2''' VMs are running.

# Switch to your '''c7host''' VM.

# Give the '''lab4-check.bash''' file execute permissions (for the file owner).

# Run the shell script and if any warnings, make fixes and re-run shell script until you receive "congratulations" message.

#Arrange proof of the following on the screen:<br><span style="color:green;font-size:1.5em;">&#x2713;</span> '''centos1''' VM:<blockquote><ul><li>Demonstrate that this VM 's current run-level is set to '''5'''.</ul></blockquote><span style="color:green;font-size:1.5em;">&#x2713;</span>'''c7host''' machine<blockquote><ul><li>Run the '''lab4-check.bash''' script (must have all <b><code><span style="color:#66cc00;border:thin solid black;font-size:1.2em;">&nbsp;OK&nbsp;</span></code></b> messages)</li></ul></blockquote><span style="color:green;font-size:1.5em;">&#x2713;</span> '''Lab4''' log-book filled out.

= Practice For Quizzes, Tests, Midterm &amp; Final Exam =

# What is the difference between '''starting''' a service and '''enabling''' a service?

# Can a service be stopped and started by issuing just one command?

[[Category:OPS245]]