DEV Community: Seb

System Monitoring Commands 📈💻

Seb — Mon, 08 Nov 2021 22:14:58 +0000

Hey everyone! I am back with another Linux article!😊

Today I will be going over basic commands you can use to monitor system performance! 📈📉💻

1. top 💻

The 'top' command is used to display active processes and how much they are using system resources.

2. lsof 💻

lsof stands for list of open files- basically shows you list of files and the processes

3. tcpdump 💻

'tcpdump' is used to analyze network traffic

4. htop 💻

'htop' is a lot like top - It's just allows you to monitor system resources or processes. As you can see, it's a bit more fancy than top

5. iostat 💻

'iostat' is a command that is used to monitor input/output devices, by telling you how long the devices have been active.

6. ps 💻

Displays the processes

7. uptime 💻

Tells you how long the system has been up

8. free 💻

'free' shows you the amount of available memory you have.

9. pidstat 💻

Used to monitor individual tasks. Great for troubleshooting issues.

10. w 💻

'w' tells you information about users logged on and their processes

That's it! Thank you for reading today's article🥳

These commands can be vital for you to monitor your system, so I will be releasing a part 2 soon, as well!😆

For future Linux and security content, please give me a follow
@linuxseb

Thank you again!😊

Working with Files in Linux 💻

Seb — Sun, 17 Oct 2021 00:06:23 +0000

Hey Dev community! 😆

After weeks of exams and dealing with imposter syndrome, I am back with another short article on 'file commands' in Linux. These are pretty useful so take a look. 🤠

1. cd 💻

The 'cd' command moves you into any directory you want. For example, if I have files located in the 'Documents' directory, this is the command I would run:

cd Documents

and this would move me to that directory.

2. ls 💻

The 'ls' command lists everything that is in that directory. To list everything in the directory, run this command:

ls -l

3. cat 💻

the 'cat' commands displays what is inside a file. Simply run this command:

cat (name of file)

The cat command also can do other things. 👇

🎯 cat > filename

Using this command, you can also create a file.

What I did below was I created the file, typed out what I needed to, then viewed the file which displayed the text I had previously written.

🎯 cat testfile1 testfile2>testfile4

Using this command, you can also create 1 new file by putting two together by doing this command:

What I did was I used test1, and test2, and merged that into a new file called test4.

4. cp 💻

The 'cp' commands copies files from one directory to another

What I did below was I copied the Goku image from the pictures directory to the example directory, used 'cd' to move into the example directory, and did ls -l to view if the picture successfully copied.

5. mv 💻

The 'mv' command is typically for moving files but it can also be used to rename files as well.

🎯 mv (to move)

To move a file into a directory, run this command:

mv (filename) (directory)

What I did below was I moved test1 from Documents to example1, I went to example1, and then listed the files to confirm if it successfully moved.

🎯 mv (to rename)

To rename a file, run this command:

mv (filename) (newfilename)

Staying in the example1 directory, I changed the name to 'newname' and then listed the files to confirm it's been changed.

6. mdkir 💻

The 'mkdir' command is what you will use almost daily. This command is used to make directories.

💻

7. grep 💻

'grep' is used to search for certain words in a text. To do this, run the command

grep (word) (file name)

8. touch 💻

'touch' is another command you can use to create a file.

9. rm

'rm' is used to delete directories or anything within them. Always be careful with this command because there is no going back once you remove something. To delete, run this command:

rm -r (name of directory or file)

10. head

'head' is used to view the first lines of a text file. You can change how many lines you want to view as well.

head -n (# of lines) (filename)

and that is it for today's article

Thank you for reading it 🥳 For future Linux content, give me a follow here or follow my twitter, @linuxseb

Installing Nginx on Ubuntu

Seb — Sat, 04 Sep 2021 23:43:16 +0000

Today I'll be showing you how to install Nginx, pronounced Engine X, on Ubuntu..

But first.. what is Nginx?

Because I want to give you the straight forward explanation of what it is..

"NGINX is open source software for web serving, reverse proxying, caching, load balancing, media streaming, and more. It started out as a web server designed for maximum performance and stability"

To read more about it, please visit their website:
https://www.nginx.com/resources/glossary/nginx/

Today I'll be going over how I installed it on my machine!

1. Update your System

Before doing anything, I always like to make sure my system is up to date. To do the same, run this command:

2. Install Nginx

Simple install it by running the command below:

3. Create new folder in /var/www

Remember, if we want to create a folder in a specific directory, we will need to move to that directory.

While in /var/www, we will create the new folder. Name it whatever you would like, and then, move into that folder, we will need to create a text file in there.

Here is an example of how to do so:

4. Create index.html file

After we move into the new folder we just created. We are going to create the text file.

I prefer to use VIM, but you can honestly use anything you want, like nano.

If you are using VIM, run the command:

sudo vim index.html

Once you've created the file using sudo vim index.html, you're going to need to edit that text file.

You first have to press 'i' to edit. You can copy what I did below as far as html tags, but you can write whatever you want between the tags.

When done, hit 'esc', type ':wq', and hit enter to quit. Now that file should be saved.

5. Create the Virtual Host

To create the virtual host, you will need to move to the correct directory first.

See my example on line 5 in the screenshot:

Once we are in that directory, we will create a new file.

sudo vim (name)

In my example, I also made the name of my file linuxseb, even though I named my folder that. I suggest creating different names for files and folders so it is less confusing, but it is up to you how you want to go about that! :)

See screenshot below, and copy what I have.

Also, don't forget!

Be sure for the server_name line and the root line to replace "linuxwithseb.com" and "linuxseb" with your correct names.

6. Restart Nginx

We are just about done. Go ahead and restart the service by running the command:

sudo service nginx restart

7. Test it

Once that has been restarted, go to your browser and type localhost:81

and...

this is what you should get!

If your website is working and it shows up, it means you've successfully installed Nginx :)

To Conclude

Tutorials like this are for beginners and for practice. Please remember to "stop" Nginx if you're not going to use it. This is just for the sake of security.

To stop it, run this command:

sudo systemctl stop nginx

and to confirm that it has stopped, run this command:

sudo systemctl status nginx

and there you go, you've now learned how to install and configure Nginx on your machine! Thank you all for tuning into my tutorial! More coming in the future :)

File Transfer Commands in Linux

Seb — Mon, 23 Aug 2021 00:08:01 +0000

Here is an overview of commands you can use when handling file transfers in Linux

Due to the fact that is a beginners article, it will just be the most basic information.

I do plan to release future articles adding more details about these commands and how to actually use them.

Since I already made this article into a tweet, you can also check that out here.

// Detect dark theme var iframe = document.getElementById('tweet-1427867248564211716-509'); if (document.body.className.includes('dark-theme')) { iframe.src = "https://platform.twitter.com/embed/Tweet.html?id=1427867248564211716&theme=dark" }

ftp

'ftp' stands for 'file transfer protocol'. You can use this, but this is an insecure way of transferring files to and from a host because when you enter your username and password it will travel over the network in plain text

sftp

'sftp' stands for 'secure file transfer protocol'. This is the secure way of transferring. Using stfp will provide a higher level of transfer protection

scp

'scp' copies files to and from a host in a secure way.

This command is considered outdated by some people and companies. It works, but use at your own discretion!

rsync

'rsync' is used to synchronize files and directories between two machines over a remote shell.

annddd

ssh

'ssh' is used to securely log onto a remote host. You can 'ssh' into a remote system using SSH keys or password authentication.

This one technically is not a file transfer command but I believe it is important when it comes to it.

Wooo!!!

annddd that is all! I do plan to post more longer tutorials and informational articles in the future!

If you enjoyed this article, feel free to give me a follow! :)

Basic Networking Commands in Linux

Seb — Sun, 15 Aug 2021 17:10:48 +0000

Hi everyone! Welcome to my first article on DEV :)

Today I will be doing a better overview of some basic networking commands in Linux.

I recently created a short and sweet thread on twitter with these commands, so right now, I will be going over them a bit more with more detail and information.

If you want to check out the twitter thread, go here - // Detect dark theme var iframe = document.getElementById('tweet-1426721727485153285-147'); if (document.body.className.includes('dark-theme')) { iframe.src = "https://platform.twitter.com/embed/Tweet.html?id=1426721727485153285&theme=dark" }

ping

The 'ping' command stands for Packet Internet Groper. It is used to test the network connections between two computers and to see if a host is reachable.

So how does it work? Well, the 'ping' command uses something called ICMP, which stands for Internet Control Message Protocol. It sends an ICMP echo request message to the IP address you request. If the connection is successful, it responds with an ICMP echo reply message. You will know the host is reachable if you get the ICMP echo reply message

dig

The 'dig' command can be used to view information about the Domain Name Servers of a website. It stands for "Domain Information Groper". Besides name servers, you can also view information about host addresses and mail exchanges. While anyone can use this command, it's mostly used by System Administrators.

whois

The 'whois' command is another basic command that is used to look up information. In this case, using whois will give you details about a domain, such as owner information.

Check out the screenshot to see what it shows you:

hostname

This command is as it says. If for any reason you need to use it, it just tells you what the hostname is.

ip a

The 'ip a' command is among a couple you can use to find your IP address. Of course, knowing what your IP address is, is important.

You can also use the IP command to view certain things. Such as 'ip link', this command will display link layer information.

finger

The 'finger' command shows you the details of all users who are logged in. This is a great command for sysadmins as well as they can see things such as exact login times and even emails of users. In order to use this command, you may need to install it. To do so, run 'sudo apt-get install finger'

netstat -a

Another useful command is 'netstat'. In this case, I am using 'netstat -a' to list all the ports that are listening.

A listening port is when your machine is ready to accept a connection on that port. You can close and open ports at anytime.

traceroute

The 'traceroute' command displays the route a packet took to reach the host. If you look at my screenshot below, you can see how many 'hops' it took for me to reach the requested host. A hop happens when a packet is passed from one network segment to the next network segment

WOW, thank you for reading all the way to the end.

I do plan on posting more about Linux in the future. Stay tuned!