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Introduction into

Operating Systems

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Linux

Linux is a OS widely used for its wide range of uses and many different distros. Each distro can be as lightweight or as heavily modified as a user needs. Popular distros include Ubuntu, Pop!Os, Fedora, and Debian. It is very important for networking and many companies around the world use it. It is massively different from windows and many systems use command line to operate.

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Linux File system

Navigating the Linux Filesystem is easy. The Linux file system is different from windows. Instead of the letters representing each drive, Linux has all files under root(/). Each drive will be listed underneath root as(/etc)

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Navigate the Linux filesystem tree

What is the pwd command an acronym for? What about the cd command?

  • pwd – Print working directory, this shows the path for the current directory
  • cd – Change directory, Changes to directory that is specified

Explain the differences between a relative path and an absolute/full path in Linux.

  • A relative path specifies the location of a directory or path within the current working directory.
  • An absolute path is the exact location of a file or directory from the top of the file system.

References:

  • Project video

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Create directories and files

You can use the tree command to view all the files and directories on the system.

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Copy and remove directories and files

You can use mkdir to make directories and rmdir to erase directories.

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Locate directories and files

You can locate files on the system by searching for them with the locate command.

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Linux Shell Scripts�

Changing the path allows a user to access a script without having to type out the entire directory in which it is located.

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Create a shell script

What are the file permissions of the script?

  • rw-rw-r– read/write for owner and read/write for group, read only for everyone else.

What’s the name of the user-defined variable in the script?

  • text

Which redirection meta-character is used in the script? What does it do?

  • redirection to the file and appends to the end of the file

References:

  • Project recording
  • Following instructions on the HyperV tutorial

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Change script file permissions

You can change the permissions of a file by doing the command chmod.

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Set the PATH variable

You can set the path variable by doing

PATH=$PATH:/any directory

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Make the PATH variable permanent

To make the path permanent you can use the command

sudo nano /etc/profile

You can then add the path modification by putting

Export PATH=$PATH:/any directory

Then closing and saving.

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Creating and removing users within Linux�

We can create new users within Linux so multiple people can use a system. It is important to give them the correct permissions so they can use the system without accessing files they should not be able to use. This is very important for security.

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Add users and groups in CLI

What does the –m option in the useradd command do?

  • -m tells the useradd command to create a home directory for the new user

What does the -3 option in the tail command do?

  • -3 tells the tail command how many lines to show from the end of the file, the default is 10

Which line of the /etc/group file lists members of the “students” group?

  • students:x:1002:student,mary

References:

  • video

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Test user and group settings

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Add users in GUI

Here we can see the user john has the same permissions as student and can use todolist.

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Remove users and groups

Users can be removed with the userdel command

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Network Configuration�

It is important to understand how to properly configure your network on Linux so you can use the internet and other networks on your system.

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Discover host IP configurations

What is the IP address of your Ubuntu machine?

  • 192.168.1.108

What is the IP address of its default gateway?

  • 192.168.1.1

What is the IP address of its DHCP server?

Answer here:

  • 192.168.1.1

What is the IP address of its DNS server?

  • 192.168.1.1

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Manage network interfaces

Which DHCP message is shown in the output of the sudo dhclient –v –r ens33 command?

  • DHCPRELEASE

Which four DHCP messages are shown in the output of the sudo dhclient –v ens33 command?

  • DHCPDISCOVER
  • DHCPOFFER
  • DHCPREQUEST
  • DHCPACK

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Using network utilities

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System Performance Monitoring�

It is important to monitor your system to ensure it is operating with full efficiency. Monitoring both your network is an important step to ensure your computer is secure and working properly.

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Monitor Linux processes

What is the default action of the 15 SIGTERM kill signal?

  • The default action is to kill the highlighted process

In the System Monitor window, click on % CPU to sort the processes by CPU load. Which process shows the highest percentage of CPU usage?

  • Gnome-shell (GUI)

References:

  • Project video

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Monitor user activities

Issue the sudo accton on command to turn on GNC accounting. Run the sudo updatedb command. Enter lastcomm updatedb to check if the updatedb command was executed before. Remember to turn off GNC accounting (sudo accton off) after.

What flag value is displayed in the output?

  • -”super user”

Why is the name of the user who ran the processes shown as root, not student?

  • superuser – since we typed sudo in front of command

References:

  • Project video

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Monitor network bandwidth usage

You can monitor how much bandwidth a program is using. This is an important step in ensuring the security of your system.

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Challenges

Although I have used Linux before I did not have much experience using the command line. I have only used it to install applications and work with small Python projects. One of my main challenges I faced when working with Linux was ensuring I remembered the many commands that are used to operate it. I have constantly forgotten many commands and had made many typos making It hard to operate at times.

Another challenged I faced was when I got to my final slide (the conclusion slide) on the project, I had accidently closed the PowerPoint and had to redo the entire thing because for some reason auto save was not enabled by default and I forgot to save. thanks Microsoft :’)

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Career skills gained

  • Working with Linux Filesystems
  • Understanding how to use the Linux command line
  • Operating and using virtual machines
  • Interacting and using server-based systems

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Conclusion

This project helped further my understanding of Linux systems and how to use their command line properly. I had learned how to secure the Linux system by properly setting permissions and assigning groups to users. I had gotten hands on experience operating a Linux system.