Linux for Everyone

Linux is an important tool especially for hackers. ethical of course.

From today (26.6.23) I will be posting Linux guides, ranging from linux commands to installing & using hacking tools.

Day 1

pwd

in GUI (Graphical User Interface), its easy to know where you are however in terminal it might not be straight forward.

Firstly, you can see above the input area however this doesn’t show the full path at times which is why we use the command is pwd which is a shortform for “Print Working Directory”.

Here you can see that the terinal just shows website but when we use the command pwd the whole path is shown.

ls

Taking forward the GUI analogy, when we open a folder we instantly see all the folders and files that are in the folder however in terminal we have the command ls to see the directories & files.

You can remember this by the word “list” so whenever you want to list all the files and directories, the command is ls.

As you can see, the folders are highlighted by blue and the files are just white/grey.

you can also use ls -a to see hidden files:

cd

cd also known as “Change Directory” is used to go in and out of folders.

Here the current directory was ‘website" and then, using cd I changed the directory to “archetypes”.

Now to go back a directory you use cd .. which takes you back one directory; to go back two directories, we use cd ../.. and you can go back as much as possible by adding ../.

For example, to go back five directories I can use cd ../../../../../

Here, I was on “archetypes” then by using cd .. I went back to “website”.

you can also use cd to go back to your home directory like so:

clear

Doing all these commands probably makes your terminal all filled, you can clear your terminal by the clear command

note:you can also use ctrl+l to clear the terminal.

cat

cat is used to print a file to your terminal. For example, in my “archetypes” directory I have a file named “default.md”.

cp

cp is used to copy a file.

We will copy the default.md file to another folder named “folder1” like so:

Day 2

mv

mv is short for move, we have to use this with care is move will delete the original file.

the usage for mv is the same as the cp command.

touch

touch is to create a text document.

nano

nano is a text file editor similar to notepad on Windows. We will edit the same file we just created, file.txt.

note: nano is a may seem very complicated for now so you may not prefer nano and can use another text editor

nano usage:

nano {file-name}

to save a file in nano, press: ctrl+X then y and then the enter key

sudo

sudo is like running a file as adminstrator. This is relavent when installing something or changing system settings like adding or removing users.

Usage of sudo is pretty straight forward, you have to add sudo before the command. For example, to install nmap the command is apt install nmap however you will get an error if you run it without sudo thus making the command as

sudo apt install nmap

grep

grep is used to pharse through outputs. For example, we will search for the word “TCP” in the nmap help page:

nmap -h | grep "TCP" 

here we get all the sentences with “tcp” in it. This can be really helpful when searching through files or text.

history

history can be used to see all the previous commands you have been using previously. There is nothing to it except you can use history & grep to fully take advantage of the history feature.

Day 3 | Managing Users

adduser

adduser allows you to add a user to your system.

syntax:

sudo adduser {username} 

passwd

passwd used to change a user’s password.

syntax:

sudo passwd {username}

usermod

usermod allows you to change user details.

syntax:

sudo usermod {username} {switches}

note: you can know switches by entering sudo usermode -h

su

su used as “Switch User”.

syntax for any user:

su - {username}

syntax for root user:

sudo su -

userdel

userdel allows you to delete a user(s).

syntax:

sudo userdel {username} 

Day 4 | Installing stuff

apt

apt is used on debian & debian based distributions like ubuntu, kali, kubuntu, et cetra

syntax for installing something:

sudo apt install {package name}

syntax for uninstalling something:

sudo apt remove {package name}

syntax for downloading updates:

sudo apt update 

syntax for installing updates:

sudo apt upgrade

git

to download custom tools from GitHub, you have to use git

syntax:

Download the tools

git clone {repository link}

Install requirements

sudo pip3 install -r requirements.txt

note: this assumes that you are in the directory which has requirements.txt

Day 5 | Daemons

Daemons are like services in Linux. This is similar to services.msc on Windows.

To check the status of a daemon:

sudo systemctl status {daemon name}

stop a daemon:

sudo systemctl stop {daemon name}

start a daemon:

sudo systemctl start {daemon name}

start a daemon on startup

sudo systemctl enable {daemon name}

stop a daemon on startup

sudo systemctl disable {daemon name}

Day 6 | Processes

ps

ps allows you to see processes running.

view processes running by a user

ps -u {username}

killall

killall is used to kill a process.

killall {process name}

sometimes a process is stuck or most commonly known as “not responding” but then you have to use:

sudo killall -9 {process name}

Day 7 | helpful things

python web server

You can use python to make a web server right in your terminal window with python.

This can be useful while hacking or just doing IT, to do this you need to install python:

sudo apt install python3 

then:

python3 -m http.server

and this will start a server on localhost:8080

this can be used to transfer files as well. The possibilities are endless.

wget

wget can be used to download a file or other web files like .html

syntax:

wget {switch} {url}

Here are more external tools that may help and will make you effective: /guides/terminal-commands/

Challenge

There is another tool like wget called curl, curl is used for hacking, the challenge is to search about curl either by Google or their help page by curl -h

that’s it <3

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