#linux terminal guide

Python:

Introduction to Variables

User Input and Selection

An Introduction to While Loops

Putting it Together

Introduction to Lists

Website:

Into to HTML

Binary:

Decimal to Binary and Vice Versa

Basic Logic Gates

Hacking:

Securing Kali Against Hacking

Finding Open Ports With Nmap

Finding Exploits

Hacking Metasploitable

Staying Safe Online:

Spotting Phishing Attacks

HTTP vs HTTPS

Good Password Etiquette

Proxies and VPNs

MultiFactor Authentication

Virtual Machines:

Kali for VMWare

Kali for VirtualBox

Creating a Live USB

Linux:

Directory Traversal and File Creation/Deletion

Basic Networking Commands

Remote Access

Finding Files

Blue Team:

Static Malware Analysis 101

General Programming:

 It happens to everyone: You need a certain file for whatever reason, but you just can’t remember where you saved it. If you’re like me organization may not be your forte and it may be easy to lose files, luckily Linux has ways of finding them. The ‘find’ command is very useful for this, but can take a while to learn. It has a variety of uses, but for this guide we’re just going to use it for finding lost files that we can remember the name of.

(Damn it, where did I save my to-do list?)

The ‘find’ command has four main parts. After the command ‘find’, you need to specify which directory to look through, then you can tell the program the type (the find command can locate both files and directories), then the name. I’ll talk about the last bit in a minute.

Finding a File:

So say I need to find a file called TODO.txt, and I know it’s in my ~/Documents directory. I can use the command ‘find ~/Documents -type f -name TODO.txt’. the ‘-type f’ flag denotes we are looking for a file, and -name is pretty self-explanatory.

Now I have the path to the file.

Finding a Very Lost File:

What if I don’t know where I saved it at all? Well then when specifying the location you use ‘/’, and the output is less pretty:

(I don’t think I have the right permissions to access some of these files)

We can see the file here, but sometimes it can be hard to find in the sea of ‘Permission denied’, this is where the trick I mentioned earlier comes into play. There is a file called /dev/null on Linux where anything written to it is lost. By adding 2>/dev/null to the end we send all errors (represented by 2) to /dev/null.

(Isn’t that much better?)

Finding a Directory:

Finding a directory works very similarly to finding a file, but you change the value of the ‘-type’ flag to ‘d’ instead:

Sometimes you need to do work on a computer, but won’t be able to do it physically. Linux has commands to enable you to use the terminal of another device across the internet. The preferred method of doing this is with a protocol called SSH.

Using SSH:

To SSH into a device, you need two pieces of information: the IP of the server, and a username on the server to log in as. I’m going to be connecting to my metasploitable VM, so I know the username is ‘msfadmin’ and I can find out the IP. I can then start to connect with the command ‘ssh [username]@[IP]

When you first connect to a server, you’ll be greeted with something looking like this. This can be used to help you authenticate that the server you’re connecting to is the one you’re intending to, but for now you can just type ‘yes’ to connect

After entering ‘yes’, you should be greeted with a login prompt, where you can enter your password (’msfadmin’ in this case) to log into the server and be given a prompt. In this example I think I took too long and the connection closed, but just restarting the connection worked.

You can now run commands as you would on your local machine:

Using SSH Instead of  Telnet:

Ping:

Ping is the networking command I use most often. It is used to test if you can reach a device, and if so how quick the connection is. To use this command, you type the word ‘ping’ followed by either a domain (google.com) or an IP address.

Ping send a stream of packets to the location you give it, and waits for a response. After running the command, we can see the response (64 bytes from...), and on the end of the line is the time it has taken to get that response in milliseconds. The ping command will run indefinitely, so to end it you use the keyboard shortcut CTRL+C. You can then get some statistics about the connection. If you don’t have a connection to the device you’re pinging, you will see something like this:

Note that ping can also be used to give you an IP address of a domain. After pinging a domain, it will give an IP address. Here I find an IPv6 address after pinging bing.com:

ip address:

This command tells you your local IP address. There’s a lot of information that may not be useful to you however.

(I used my own Kali machine for this, because my tutorial one has too many IPs and the output was cluttered)

For a start, we can ignore everything in section 1. This is the loopback interface and while it can be useful for diagnosing connection problems, it doesn’t tell us our IP: for that we need to look at section 2. Your internal IP address is listed under inet (in this case it’s 192.168.129.132), with your IPv6 address listed under inet6.

That is a lot of information to take in, but all you really need to know is that your IP address on your current network is found next to ‘inet’.

Conclusion: