🔎

Eth0: External 10.9.0.0/24

Eth1: Internal 192.168.60.0/24

Linux Useful Commands

⚠️

These commands were tested on Ubuntu 18.4 server and were working fine.

Install any software on Linux

# You should find it in .dep file formate
# Then extract it by this command below
# Finally call it by its name to run it
# Below I am installing google chrome
sudo dpkg -i google-chrome-stable_current_amd64.deb

google-chrome

Search for a text in a directory or a folder

grep -rnw '/path/to/somewhere/' -e 'pattern'

r or R is recursive,

n is line number, and

w stands for match the whole word.

l (lower-case L) can be added to just give the file name of matching files.

e is the pattern used during the search

Start a service in Linux

sudo systemctl start ssh

sudo service ssh start

Show the IPv4 address you got:

ifconfig | grep "inet "

How to get a directory downloaded from a URL using wget

# -r: flag is for recursice 
# --no-parent will ignore the index.html file 
wget --no-parent -r http://WEBSITE.com/DIRECTORY

Find and delete duplicate files using `fdupes`


# Description: Find and delete duplicate files.
# Example: fdupes -rdN /path/to/directory
fdupes -rdN /path/to/directory

Return the public ip address of a machine

curl https://ipinfo.io/ip ; echo

	# ========= try this too

dig +short txt ch whoami.cloudflare @1.0.0.1

# ====== try wget without a server running on the machine 

wget <ip_server>
# use tcpdump to retrieve the ip filter with TCP protocol.

Using Wget to download all files on a web server directory:

wget -r -np -nc -nH --tries=3 --timeout=30 --waitretry=5 --random-wait --no-check-certificate -q --show-progress "http://server:8080/folder/"
# the folder with all its content will be downloaded here
# You can use ptyhon -m http.server 8080 //to create a webserver for your content.

Network diagnostic tool mtr :

#Description: Network diagnostic tool that combines traceroute and ping.
#Example: mtr 8.8.8.8
mtr 8.8.8.8

join command is used for joining lines of two files on a common field

join file1.txt file2.txt > joined.txt

2) Command: let

The let command in a single-line bash command:

let "sum = 5 + 2"; echo "Sum: $sum"

Output:

Sum: 7

the let command is used to calculate the sum of two numbers (5 and 2) and store the result in the variable sum. The echo command is used to display the value of the sum variable.

Change a mode of a wifi adapter to be monitored

# First disable your adapter by this command
sudo ifconfig wlan0 down 
# Do this command to kill any process that may interfer with
# with the adapter. 
sudo airmon-ng check kill
# Enable monitored mode
sudo iwconfig wlan0 mode monitor
# Finally enable the adapter back
sudo ifconfig wlan0 up
# Check your result by 
sudo iwconfig 
# wlan0 IEEE 802.11b  ESSID:""  Nickname:"<WIFI@REALTEK>"
# Mode:Monitor

Changing the MAC of your machine

# Disable the interface that you want to modifie 
sudo ifconfig wlan0 down 
# Change you MAC to whatever you prefer but make sure it start 
# with 00:xx:xx:xx:xx:xx
sudo  ifconfig wlan0 hw ether 00:11:22:33:44:55

# Power up your network interface
sudo ifconfig wlan0 up

# Check the result 
ifconfig 

# The MAC you changed is temporarily. It will get back to its 
# original once you reboot your machine. 
# BSSID ==> the MAC of that network adapter.
# PWR ==> the power of the signal or the strength higher the better.
# Beacons ==> a number sent by the network to prodcast t heir exesting 
# Data ==> the number of data in packets. 
# /s ==> the number of data collected in that network.
# CH ==> the channel that the network run on.
# MB ==> Maximum speed supported by the network.
# ENC ==> the Encription used [WPA,WPA2,OPN,etc].
# CIPHER ==> the cipher used in the network [CCMP,WEP,etc].
# AUTH ==> authentication used in the network.
# ESSID ==> the name of the network

Logging out a user using ssh (log out from all sessions)

# Check who is logging in currently 
who

# Do this command that send a KILL signal to the user. 
sudo pkill -SIGKILL -u <username>
# or
loginctl terminate-user <username>
# double check if that user got dropped.
who

Packet Sniffing on monitor mode adapter [Airodump-ng]

# This is a part of aircrack-ng tool.
# It is used to capture all packets within the range.
# display detail info about network SSID around us. 
# Display connected clients.
# wlan0 can be any other adapter name 
sudo airodump-ng wlan0
# To quit it hit Ctrl+C to exit
# You can use the --band a to capture 5g bands frequencies network
sudo airodump-ng --band a wlan0
# To capture both band 2.4G and 5G use the --band abg
sudo airodump-ng --band abg wlan0

# Specifiy a SSID to sniff on provide[ --bssid 00:11:..:55 --channel 
sudo airodump-ng --bssid  00:11:C3:2C:13:55 --channel 136 --write sniff wlan0 

# The output table has all the clients connected to this network 
# the BSSID ==> the MAC of the network we sniffing 
# the STATION ==> are the clients MACs 
# the Frams ==> how many frames we collected about this clients

Know who is currently logged in your machine

# Using the users command will print the name of the users 
users
# Lists all users currently logged into the system along with their login time, idle time, process ID, and more.
# The -a option lists all users, including system users and users without a terminal session.
# The -H option prints the output in a format that is easier to read.
who -a -H

# You can also capture these information using this command
w

Know the last modified files in a directory

To know the last files modified, you can use the ls command with the -lt option, which will list files in the current directory sorted by modification time, with the most recently modified files listed first.

ls -lt

You can also use the find command to search for files modified within a certain timeframe. For example, to find all files modified in the last 24 hours, you can use:

find /path/to/directory -type f -mtime -1

Storing bash command and execute it by its name

$ COMMAND=("stat" "/var/log/httpd/access_log" "|" "grep" "Modify")
$ ${COMMAND[@]}
COMMAND[0]="stat"
COMMAND[1]="/var/log/httpd/access_log"
# You can commbind all of it in one string too.

Generate random MAC address:

Save it into file and executed using
Change the mode by Chmod +x NameOfFile.sh

#!/bin/bash
hexcharsC="0123456789ABCDEF"
hexchars="0123456789abcdef"
end=$( for i in {1..6} ; do echo -n ${hexchars:$(( $RANDOM % 16 )):1} ; done | sed -e 's/\\(..\\)/:\\1/g' )
echo 8c:85:90$end

Using openssl command:

openssl rand -hex 6 | sed 's/\\(..\\)/\\1:/g; s/.$//'

Check the OS version you are using

# This will print out the version and the distribution of OS you are running
lsb_release -a 
		No LSB modules are available.
		Distributor ID:	Ubuntu
		Description:	Ubuntu 22.04.1 LTS
		Release:	22.04
		Codename:	jammy
# You can cat the os-relase to print the OS version 
cat /etc/os-release

Find all hard drive connected to the machine

# show only hard drive
sudo lshw -class disk
# show CD rooms
sudo lshw -class disk -class tape
lsblk -o KNAME,TYPE,SIZE,MODEL
# this will show the GPU 
lspci | grep -i vga
lspci | grep -i --color 'vga\|3d\|2d'
ubuntu-drivers devices
# https://linuxconfig.org/how-to-install-the-nvidia-drivers-on-ubuntu-22-04
find  /usr/lib/modules -name nvidia.ko -exec modinfo {} \;

# ======== Tensorflow ======
# https://www.tensorflow.org/guide/gpu
import tensorflow as tf
print("Num GPUs Available: ", len(tf.config.list_physical_devices('GPU')))

To check linux architecture [arm,amd,etc]

# Check what operating system your server runing 
uname -a

# print if the Architecture is x86-64 or some other.
uname -m
# This will print out all the specification of you machine
cat /proc/cpuinfo

How to read Hexdump formate file

something that look like this can be opened using the command xxd -r this command read hexdump file and you can output it into another file.

# read the hexdump data.txt and save it into output file
xxd -r data.txt output

Hash sha1 a folder or a directory

tar -cf - ./{the folder} | sha1sum

Change MAC address

shut down your interface

sudo ifconfig eth0 down
# OR use this depends on your interface
sudo ifconfig en0 down

# Will change it a mac you specifiy
sudo ifconfig en0 ether RA:ND:OM:MA:C0

Check your MAC address:

# Will return your Mac address
ifconfig en0 | grep ether

After that you should bring it up

sudo ifconfig eth0 up

# OR use this depends on your interface
sudo ifconfig en0 up

Check the CPU type

lscpu
# -- or --
cat /proc/cpuinfo

Check Memory

cat /proc/meminfo
free
top

Remove the cache or clear the cache

 sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches'

Downloading directory using Wget

To avoid downloading the auto-generated index.html files, use the -R/--reject option

use -r for recursive and -np for no parent:

# wget recursive with no parent
wget -r -np -R "index.html*" http://example.com/configs/.vim/

Check CPU

lscpu

Check wireless adapter

iwconfig

# ip a
# ip r to routing table
# ip n niegbor same as [arp -a] table

show a list of all Mac addresses table

arp -a

show routing table of your machine

# It can tell you where traffic exit
route

List all the apps installed in Linux

apt list --installed

Firewall:

install ufw

sudo apt-get install ufw

Check the status of the firewall:

sudo ufw status

Enable firewall:

sudo ufw enable

Disable ufw:

sudo ufw disable

Check the rules of the firewall:

sudo ufw status verbose

Check the rules of the firewall numbered:

sudo ufw status numbered

Add a rule in firewall:

sudo ufw allow in "Apache Full"
sudo ufw allow 22

Remove a rule from the firewall:

sudo ufw delete allow ssh
sudo ufw delete allow 80/tcp
sudo ufw delete —> sudo ufw status numbered

Remove a user from a group:

sudo deluser --remove-home <user-name>
# --remove-all-files
# to remove all file

 passwd -d username groupname

passwd -d <>

Add a user to sudo group: ( change user mode)

usermod -aG sudo <user-name>

Find the largest folders in size on a directory

du -h --max-depth=1 | sort -rh | head -n 10

Find the largest files in size in a directory

ls -lSh | head -n 10
ls -lShR | grep '^-' | head -n 10
find . -type f -exec du {} + | sort -rn | head -n 10

ls -lSh:

l: Displays the long listing format, showing file sizes and other details.
S: Sorts files by size, largest first.
h: Makes file sizes human-readable (e.g., KB, MB).

grep '^-': Filters only files (since directories are listed with a d at the beginning, and files have ).
head -n 10: Shows only the top 10 results

Change Hostname on Ubuntu 20.04 (No Reboot Required)

If you wish to permanently change the hostname without rebooting your computer, use the hostnamectl command.

on Mac this file is under /etc/hosts

How to ssh without ip (using domain name)

# in your local machine the client do this 
# add this bottom line to the file /etc/hosts

##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1	localhost
255.255.255.255	broadcasthost
::1             localhost
128.4.26.211    brserver

you can set the allowed ip to ssh to machine

/etc/hosts_allow
/etc/hosts_deny

To change username and user's groupname (it is probably best to do this without being logged in):

sudo usermod -l newUsername oldUsername
sudo groupmod -n newUsername oldUsername

This however, doesn't rename the home folder.

To change home-folder, use

sudo usermod -d /home/newHomeDir -m newUsername

Step 1: Use set-hostname to Change the Hostname

Type the following command:

hostnamectl set-hostname new-hostname

Use your own hostname choice instead of new-hostname.

Step 2: Use hostnamectl to Confirm the Change

Just like the hostname command, if successful, hostnamectl set-hostname does not produce any output. Therefore, use hostnamectl to check the result.

Add a user

# -m to create with it a home directory otherwise it will have no home
sudo adduser -m <username>
# -d will specify where is location for the directory
useradd -m -d /PATH/TO/FOLDER USERNAME
# to jump to that user 
su - <username>

###### NOTE #### 
# after the creation make sure to add pass for it.
passwd USERNAME 

## To change the root from a sudo account do
sudo passwd root

Generate random password

# This will result in 12 charecters. You can change it to whatever.
openssl rand -base64 12
# This does the same when no openssl 
< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c12

Delete or Remove user

sudo deluser USERNAME

Check that you have sudo right

sudo -l
# If this command return (ALL)ALL that mean you are sudo user

To check if user is been added

# This will print the name of users
ls /home

Check your username

whoami

Switch to user or change to user

su AnyUserName

Show or Display all groups:

groups

disk free size, file management:

Free, used disk space:

# check disk free space 
df

#displays the usage on your primary hard drive
df -h /

# find a disk usage 
du -sh

List all disks on linux

lsblk
lsblk -f
# Here is a better command 
sudo lshw -class disk

# this will list all the disk too 
sudo fdisk -l

Linux crontab command

the crontab command opens the cron table for editing. The cron table is the list of tasks scheduled to run at regular time intervals on the system.

crontab [-u user][-l | -r | -e] [-i] [-s]
# file -> Load the crontab data from the specified file. If file is a dash ("-"), the crontab data is read from standard input.
# -e -> Edit the current crontab, using the editor specified in the environment variable VISUAL or EDITOR.
# Same as -r,removes but gives the user a yes/no confirmation prompt before removing the crontab.

'crontab' in Linux with Examples - GeeksforGeeks

The crontab is a list of commands that you want to run on a regular schedule, and also the name of the command used to manage that list. Crontab stands for "cron table, " because it uses the job scheduler to execute tasks; itself is named after "chronos, " the Greek word for time.

www.geeksforgeeks.org

'crontab' in Linux with Examples - GeeksforGeeks

Change the IP of an UBUNTU server (Configure static IP):

Change the user to root

sudo su -

Edit the interfaces file

vi /etc/netwrok/interfaces

Add these lines toward the end of the file

iface ens160 net static
    address the:IPv4:address:needed
    netmask 255.255.254.0
    gateway 128.0.0.1 —> find the command up to find it
    dns-nameserver 8.8.8.8

Now you need to restart the interfaces

/etc/init.d/networking restart

Check your network ping google.com

# if you try it with -c 1 it will do just one.
ping google.com
# Or you can ping its IP address
ping 8.8.8.8

Ping local machines:

ping 128.X.X.X

check your IP address

 ifconfig

Show the routing packet takes in your network

ip route

Show the default gateway IP address

ip route | grep default

Install MySQL server:

sudo apt-get update
sudo apt-get install mysql-server
sudo mysql-secure-installation utility

Open the port from MySQL server 3360

sudo  ufw allow mysql

Enable MySQl server

sudo systemctl enable mysql

Start MySQL server

sudo systemctl start mysql

📌

You can use the previous command with parameters like [ start, stop, status ]

Check if MySQL running and enabled

sudo systemctl status mysql

Export database into a file.sql

# This run on a local sql server
$ mysqldump -u USER_NAME -p DB_NAME > file_name.format

# For external sql server
$ mysqldump -u USER_NAME -p DB_NAME -h 192.168.0.15 > file_name.format

Import .sql file into a database

# This run on a local sql server
$ mysql -u USER_NAME -p DB_NAME < file_name.sql

Change between users:

su username

Change user to root:

⚠️

If you run the following command with a sudo; you can enter the root user's password.

sudo su -

⚠️

And if your user is in the sudo group you can just run it like this:

su -

See files sizes on current directory:

sudo find . -maxdepth 1 -mindepth 1 -type d -exec du -hs {}\\; | sort -hr

Find a move files that match the filter

find .  -iname "*14:01:23*" -type f -print0 | sed "s/.\///g" | xargs -0 -I {} mv {} 14-1-2023

Remove a single file, delete a file:

rm filename

Remove files with prompting configuration:

rm -i  *.pdf

Remove all files with the same extinctions, delete files :

⛔

Do not use this command until you are sure about what you are doing!

remove all files at the current directory

rm -rf *.pdf

# another example
rm -rf .mkv

Print with color in bash

📌

You can use multiple colors in bash

Reset

# To rest the text to normal color
Color_Off='\\033[0m' 

#### initializing some colors
Red='\\033[0;31m'          # Red
Green='\\033[0;32m'        # Green
Yellow='\\033[0;33m'       # Yellow
Purple='\\033[0;35m'       # Purple
Cyan='\\033[0;36m'         # Cyan

Echo in color

# This will echo in Red color
echo -e "$Red Hello World! $Color_Off"

Check the services running


service --status-all

Add script to run when reboot, run a script when startup, startup script: (crontab)

Open and edit crontab:

crontab -e

Example When reboot run bash script after 60 sec: (add to the crontab file) -f : Request to go to background -N: Do not execute a remote command. Used for forwarding ports -R: Specifies that connections to the given socket on remote server -T: Disable pseudo-terminal allocation.

@reboot sleep 60 && ssh -f -N -T -R 22222:localhost:22 -i /home/teddy/.ssh

Install Apache server

update and upgrade your machine

sudo apt-get update && apt-get upgrade -y

Install apache2

sudo apt-get install apache2

Check if the Apache2 is running:

sudo systemctl status apache2

Make sure that the httpd running when the machine load up

sudo chkconfig httpd on

See all processes currently running:

See all processes of all other users:

ps -aux

if you want to see only ssh processes:

ps aux | grep ssh

if you want to see just the first 10

ps aux | head -10

See the routing table (Netstat):

Is a network statistic tool used to list active connections from and to your computer

show all active connections on your machine

netstat -ano

Show protocol-cloned routers, n to show numbered domain names.

netstat -anr

Show routing table or the route the packet takes. It shows the "default gateway"

netstat -rn

netstat -r

netstat -an

netstat -n

Check and see if a port is used(open). Check if a port used 9191

netstat -tulnp | grep 9191
# To spit out all the port that your system Listening on
netstat -tulpn | grep LISTEN

SSH:

Install SSH

sudo apt-get install openssh-server

Start / enable SSH server

# Fist this you have to enable it to be able to start it
sudo systemctl enable ssh
# Then you can start it
service ssh start
# or you can start it using this command
sudo systemctl start ssh
# On macOS
sudo launchctl stop com.openssh.sshd
sudo launchctl start com.openssh.sshd

SSH config file:

# the ssh config file is located on this folder 
cd /etc/ssh/
# nano into the file sshd_config to edit the configuration 
nano ssh_config

How to SSH without a password

📌

Steps to ssh without password

Generate an ssh key:

# this will generate a public and private keys stored on ~/.ssh
ssh-keygen -t rsa

Move the public key to the authorized_key on the server.

cat ~/.ssh/id_rsa.pub | ssh [email protected] "cat - >> ~/.ssh/authorized_keys"

# in Mac it should be in /var/root/.ssh/id_rsa
cat /var/root/.ssh/id_rsa.pub | ssh [email protected] "cat - >> ~/.ssh/authorized_keys"

⚠️

Note: - The ssh-keygen -t rsa >> should be executed on the local machine - The private 'id_rsa' should be located on the local machine on ~/.ssh/id_rsa.pub folder. - The public 'id_rsa.pub' should be moved to the remote server on ~/.ssh/authorized_keys

Steps you need to do on some servers:

You have to create the .ssh directory and the authorized_keys file the first time.

Create the .ssh directory:

mkdir ~/.ssh

Set the right permissions:

chmod 700 ~/.ssh

Create the authorized_keys file:

touch ~/.ssh/authorized_keys

Set the right permissions:

chmod 600 ~/.ssh/authorized_keys

The permissions are important! It won't work without the right permissions!

Now you can add the public key to the authorized_keys file:

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

Nmap

Is a Network mapping tool. That means it's used to discover informations about hosts on a network (their ip, open ports, etc)

When port scanning with Nmap, there are three basic scan types. These are:

TCP Connect Scans (sT)
SYN "Half-open" Scans (sS)
UDP Scans (sU)

Additionally there are several less common port scan types, some of which we will also cover (albeit in less detail). These are:

TCP Null Scans (sN)
TCP FIN Scans (sF)
TCP Xmas Scans (sX)

📌

Install Nmap:

sudo apt install nmap -y

Scan a host :

nmap hostIP

Scan when ping is blocked

nmap 128.175.13.74 -Pn

Scan for TCP open ports at a host

nmap hostIP

Scan for UDP open ports at a host

nmap -sU -F localhost

Scan TCP services running with their version

nmap   -sV localhost

Scan the OS (Operating System) of a host with ping

sudo nmap -O localhost

Scan the OS without ping

sudo nmap -Pn -O localhost

Access all server files locally, share access files on the server (sshfs)

In your, Mac install sshs from brew.
brew install sshfs
You can install the most recent version of fuse from here: link to Fuse latest version Now mount the folder to your local machine
sshfs [email protected]:/  ~/Desktop/

Open Jupyter notebook from terminal

You need to be on the home folder
cd ~
The open jupyter by typing this command

Numerical Base Conversions

by hand:

Base conversion

Convert Decimal to Binary

# ibase is the output base here is 2 (binary)
# the number passed is 11010101 
echo "obase=2; 23" | bc

Decimal to Octal number

# ibase is the output base here is 8 (octa)
# the number passed is 23 
echo "obase=8; 23" | bc

Decimal to Hex number

# ibase is the output base here is 16 (hexa)
# the number passed is 23 
echo "obase=16; 23" | bc

Decimal to any base number

# ibase is the output base here is 4 
# the number passed is 23 
echo "obase=4; 23" | bc

Binary to decimal

# ibase is the output base here is a decimal
# the number passed is 11010101 
echo "ibase=2; 11010101" | bc

Oct to decimal

# ibase is the output base here is 8
# the number passed is 723 
echo "ibase=8; 723" | bc

You can use the bc directly by

# To lunch bc 
bc 
# Then specifiy the inpute and the output base you wish 
ibase= 10
obase= 2
7
111
# This will show the binary output of 7 integer.

Open Jupyter on a server with Tunneling

# The first part is the regular ssh -NL to open that tunnel on localport:localhost:serverport 
ssh username@nameOfTheServer  -NL localport:localhost:serverOpenedPort

# run jupyter in the remote server background (keep it runing in the backgraound)
jupyter lab --no-browser --port=8888 &
jupyter notebook  --port=8082 --ip=0.0.0.0 --no-browser --allow-root &

# find jupyter notebook token after been closed
jupyter notebook list 

# Jupyter does not delete file it store them here
~/.local/share/Trash

Check the ram slots in your machine

sudo dmidecode --type 17

Check what GPU machine has installed

sudo lspci -v | less
sudo lshw -C display
nvidia-smi

Check the machine details (Factory, model, type ,etc)

sudo lshw | grep product | more

Nmap [Port Scanning]

# A = Look for Everything -p- = in All ports
nmap -T4 -A -p-

Open proxies on Saudi 🇸🇦

PORT	ANINYMITY TYPE:	CHECKED: Oct-22, 19:42	COUNTRY:	CITY:	ISP

8080	ANINYMITY TYPE: transparent	Oct-22, 20:05	Saudi Arabia	Riyadh	Arabian Interne...
8080	ANINYMITY TYPE: transparent	Oct-23, 02:07	Saudi Arabia	Khobar	SaudiNet
8080	ANINYMITY TYPE: transparent	Oct-22, 20:05	Saudi Arabia	Unknown	Arabian Internet

iCloud Document directory in MacOs

# Make sure you update the cokmmand to match your username.
cd /Users/username/Library/Mobile Documents/com~apple~CloudDocs

Install zsh

sudo apt install zsh 

# check a defualt shell 
echo $SHELL 

sudo chsh -s `which zsh`
# Start setting up zsh 
zsh
 
# change the defult shell for a user


# Return the zsh to defualt bash shell  
sudo chsh -s /bin/bash <username>

Install anaconda via homebrew

# brew command for anaconda
brew install --cask anaconda

# the path of anaconda =/usr/local/anaconda3
# if anacond was not found or access by zsh 
export PATH="/usr/local/anaconda3/bin:$PATH"
# if this was installed through brew it can be found under 
# /opt/homebrew/anaconda3/bin
export PATH="/opt/homebrew/anaconda3/bin:$PATH"
# update your source .zschrc
source ~/.zshrc

Update the $PATH on Mac

# remove something from $PATH or update it. 
echo $PATH # and copy it's value. and remove what you don't need to be there. 
# empty it 
export PATH="" 
# keep what you like.
export PATH="/path/you/want/to/keep"

Kill a process in Linux

# kill ProcessID
kill -9  10389

# you can find a process by 
ps -eaf | grep "process_name" | grep -v grep| awk '{ print $2 }'

# kill the process one liner command
ps -eaf | grep "jupyter" | grep -v grep| awk '{  print $2 }' | xargs kill -9

Check where a package installed via brew

#Use the following to show the installation path of a package:
brew info anaconda

Copy file from a remote host to local host SCP example:

scp username@from_host:file.txt /local/directory/

Copy file from local host to a remote host SCP example:

scp file.txt username@to_host:/remote/directory/

Copy directory from a remote host to local host SCP example:

$ scp -r username@from_host:/remote/directory/  /local/directory/

Copy directory from local host to a remote host SCP example:

$ scp -r /local/directory/ username@to_host:/remote/directory/

Copy file from remote host to remote host SCP example:

$ scp username@from_host:/remote/directory/file.txt username@to_host:/remote/directory/

Copy files from source to destination without overwrite

# -n will copy all the files without overwriting in the destination
cp -n *.jpg ./copy

Make a directory

# directories called sa1,sa2,...,sa50
mkdir sa{1..50}
# same previous but each one has sax1,sax2,...sax50 inside
mkdir -p sa{1..50}/sax{1..50}
# 26 directoried a12345,b12345,...,z12345
mkdir {a-z}12345
# directories 1,2, and 3 
mkdir {1,2,3}
# today's date with formate year month day and inside it has 1,2 and 3 
mkdir -p `date '+%y%m%d'`/{1,2,3}
# the username and inside it has three directories 1,2, and 3
mkdir -p $USER/{1,2,3}

Date command

These are the most common formatting characters for the date command:

%D – Display date as mm/dd/yy
%Y – Year (e.g., 2020)
%m – Month (01-12)
%B – Long month name (e.g., November)
%b – Short month name (e.g., Nov)
%d – Day of month (e.g., 01)
%j – Day of year (001-366)
%u – Day of week (1-7)
%A – Full weekday name (e.g., Friday)
%a – Short weekday name (e.g., Fri)
%H – Hour (00-23)
%I – Hour (01-12)
%M – Minute (00-59)
%S – Second (00-60)

Download and install .sh file one command

curl -fsSL https://link.sh | sh

Docker

# install docker 
sudo apt install -y docker.io
# how to enable docker
sudo systemctl enable docker --now

# to start docker after been closed 
sudo systmctl start docker 

# Add the user to the docker group Do the following command to refresh USER
sudo usermod -aG docker $USER
# sometime you run into premission denied 
newgrp docker

# how to run hello world in docker
docker run hello-world
# apache server with DVWA (Damn Vulnerable Web Application)
docker run --rm -it -p 80:80 vulnerables/web-dvwa
# Let the DVWA open apache server and connect to it using any browser and serfe to localhost 127.0.0.1
# The user name is admin and the password is admin too 
# you need to go down and reset the database and re-login
# the user is admin and the password is password now. 

# Installing OWASP juice shop
docker run --rm -p 3000:3000 bkimminich/

# to remove a docker image 
docker image rm -f IMAGE [IMAGE...]

# to list all the docker images 
docker image ls 

# to inspect a docker image architecture 
docker image inspect [IMAGE...]

For Kali Linux

If you want to fix problem with Kali linux look for this guy called [Dewalt-arch]

# download the tool to fix kali issues [pip,pip3,golang gedit ,etc.]
git clone https://github.com/Dewalt-arch/pimpmykali

# navigate to it
cd pimpmykali

# run it with option 0 to fix all 
sudo ./pimpmykali.sh

#For a new kali vm, run menu option N

Bash Scripting

# it is going to ping one time and store the result in that file.
# use >> to concatinate or append at the end of a file.
ping 10.10.10.1 -c 1  > test.txt

# will grap the line that has the occurance of 64 bytes
# will split that line by Delimiter space and get the Field number 4 
cat test.txt | grep "64 bytes" | cut -d " " -f 4

# the result will be >> 10.10.10.1

Installing Python2 and Python3

# This will get you Python 2.7 installed 
sudo apt install python2
# This will get you the latest Python 3.X version 
sudo apt install python3

Installing pip and pip3 in your machine

# This will install pip in your machine
sudo apt install python3-pip
# To check pip version 
pip --version 
# This will install pip2 in your machine
sudo apt install python-pip

Jupyter lab

# install jupyterlab 
pip install jupyterlab

# start jupyter lab 
jupyter lab /path/you/want

Open Jupyter remotly


# In the remote server that has jupyter. You open jupyter witout browser and on specified port 
jupyter notebook --no-browser --port=8888

# From local machine that has the GUI do 
# Open ssh tunnel to your server and tie your local port to the server one localPort:localhost:remotePort
ssh -L 8888:localhost:8888 your_server_username@your_server_ip

Compressing tools

⚠️

To check what kind of compressor tool used you should use the command file.

file File.bin 
# File.bin: gzip compressed data, was "data9.bin",
# last modified: Thu Sep  1 06:30:09 2022, max compression,
# from Unix, original size modulo 2^32 49

TAR ( Software utility for collecting many files into one archive file and Extraction)

# ============= Compress ==================
# How to compress a whole directory in Linux or Unix
# You need to use the tar command as follows (syntax of tar command):
tar -zcvf archive-name.tar.gz source-directory-name

# ============= Decompress ================
# File should have extension like .tar
# Can be any compressed file. This command can uncompress most of the compressed files type such as zip,gz,tar,bz ,etc
tar -xvf FILE.GZ.TAR

tar -xzf FILE.GZ.TAR
# === This for bzip
tar -xjvf FILE
# =====Verbose 
tar -xvzf /path/to/file.tar.gz 
# ================ Split files into chunk ==============
tar czpvf - /image_data | split -d -b 6000M - malnet-image
# this will result into spliting the files into chunk of 6G each chunk in size

# To combined all these fiels back again do
cat malnet-image* | tar xzpvf -

bzip2

# File should have extension like .bz2
# This command to compress the file.
bzip2 File 
# This command to uncompress a file .
bzip2 -d File.bz2

gzip

# File should have extension like .gz
# This command to compress the file.
gzip File 
# This command to uncompress a file .
gzip -d File.gz

Adding a path to your PATH directory

export PATH=$PATH:/user/any/place/you/wont/to/add/bin 
# After updating any environment variables make sure to update the profileby 
source ~/.profile 
# In case you are using zsh do 
source ~/.zshrc
# To chek if the path get addedd successfully do 
echo $PATH

Environment Variables:

# This will print all the environment variables  
env
ENV
#This variable displays all the environment variable.

# Standard environment variables are as follows:
PATH
#This variable contains a list of directories in which our system looks for files. It separates directories by a (:) colon.

USER
#This variable holds the username.

HOME
#This variable holds the default path to the user's home directory.

EDITOR
#This variable contains the path to the specified editor.

UID
#This variable contains the path to the user's unique id.

TERM
#This variable contains the path to the default terminal emulator.

SHELL
#This variable contains the path to the default shell that is being used by the user.

Create Environment Variable

# To create a new variable, use the export command followed by a variable name and its value.
export NAME=VALUE

#To create a new variable say new_variable, execute the command as follows:
export new_variable=10  
# The echo command is used to display the variable:
# To display the value of the variable, use the $ symbol before the variable name:
echo $new_variable
# add java JDK to path
export PATH=$PATH:/home/jdk1.8/bin/

Removing an Environment Variable

unset new_variable

AWK

# print counter that count the number of the 14 columns
awk '{t+=$14; print t,$14}'
# this will change the list of names in the bad_ to names ends with _ and save it to aaa 
cat bad_ | awk '{print "mv " $1 " " $1"_"}' > aaa
# You can execute commands by place in it between ``
awk "{print `ls` $1}"
# You can do some calculation 
awk '{print  $1+$3 +$5}'

# remove the first three lines from a file 
awk 'NR > 3 { print }' < t.txt

# remove the first and the last line in a file
awk 'NR>2 {print last} {last=$0}'

# Awk set delimiter as comma 
awk -F',' '{print $3}' myfile.txt  

# Sum all the scond values on a file
awk '{n += $2}; END{print n}'  <file-name>


#If you want to print each comma-separated value on a separate line using awk, you can use the following command:
awk -F, '{for (i=1; i<=NF; i++) print $i}'

egrep '^Hits@level = ' log | awk '{t+=$14; print t,$14}' echo ===== summary '[5]' egrep ' \[5\] .:' log | sort -u | pr -t -n #egrep ' \[5\] .:' log | egrep -aiv testsuite | sort -u | pr -t -n

Hostname

# Hostnamae what comes after the user@xxx this can be viewed by
hostname
# Or you can see more details by 
hostnamectl 
# To change it use 
hostnamectl set-hostname 'whatever you wish'
# reboot 
sudo reboot

Timing a command

# If you want to time a command or a script 
time AnyScript

# Display a time when a file is created 
ls -lt FileName

Links and Lynx change html format into text

lynx -dump FILE.html

Sed replace char or symbol by another

# this will replace any white space with a tab 
sed -e 's/    /\t/g' 
# This will replace any white space with a comma
sed -e 's/ /,/g'

Memory Layout

List only directory

Type the following command:

$ ls -l | grep `^d'
$ ls -l | egrep `^d'

Or better try the following ls command only to list directories for the current directory:

# This will list all the directories in the current directory
ls -d */
# If you want to delete all the directories but not the files do this 
# this will remove all the directories recursivly 
for i in `ls -d */`;do rm -rf "$i";done

Find files modified within 7 days

# Current directory find any file that ends in c or h that has been modified within 7 days.
find . -iname "*.[ch]" -mtime -7
# You can add more extension the the top command by -o -inmae "*.html" this will cover the html files. 
find . -iname "*.[ch]" -o -inmae "*.html" -mtime -7
#----------------
# d - directory
# f - file
# l - symbolic link
# s - socket
# p - named pipe (used for FIFO)
# b - block special (usually a hard drive designation)
#-----------------
# Is an option to specify the depth or the scope of search "-maxdepth 2" here is 2 level below this directory 
# find type file in the root directory
find / -type f -name apache2

Find and execute commands on the output of the file

# Here we execute the ls -la as a command on the output of the first command
find . -iname '*.' -exec ls -la {} \;

# Here we print the length of each file in lines.
find . -iname '*.png' -exec wc -l    {} \;

#We can also pass a file of scripts to be executed on the output, -name not case sensitive. However, -iname is not case sensitive   
find . -name '*.php' -exe Script {} \;

# Script example below 
cat Script 
# This print the without spaces or new lines
echo -n "$1 "
egrep 'printf\(' $1 | wc -l

Uname

prints the name, version and other details about the current machine and the operating system running on it.

# -m, (--machine) - Prints the name of the machine’s hardware name.
# -p, (--processor) - Prints the architecture of the processor.
# -i, (--hardware-platform) - Prints the hardware platform.
# -o, (--operating-system) - Print the name of the operating system. On Linux systems that is “GNU/Linux”
# -a, (--all) - When the -a option is used, uname behaves the same as if the -snrvmo options have been given.

uname -a

id

If the username is omitted, the idcommand displays information about the currently logged-in user.

# id prints the real user ID (uid), the user’s real primary group ID (gid), and real IDs of the supplemental groups (groups) the user belongs to.
id

Remove a program from Linux

sudo apt remove AppNAME
sudo apt purge AppName
sudo apt autoremove 

# Make sure to remove all its files if you know where it lives.
whereis AppName 
rm -rf  ...# all the previous location

Download a file Wget

wget theURLofTheFile

Update Linux apt-get repository


#This will update your apt list 
sudo add-apt-repository ppa:ubuntu-elisp/ppa
# You need to apt update after that
sudo apt-get update
# Then install your newer version of your package 
sudo apt-get install emacs-snapshot

locate a program and its files

#Searching with locate
 locate ProgramName

Snort: world’s best network intrusion detection system (NIDS)🐷

Snort is a free open source network intrusion detection system and intrusion prevention system created in 1998 by Martin Roesch, founder and former CTO of Sourcefire. Snort is now developed by Cisco, which purchased Sourcefire in 2013. commonly used to detect intrusions by hackers

Display line number on files

nl /etc/snort/snort.conf

Changing your ip address

fconfig eth0 192.168.181.115
# you can also change the netmask , the broadcast
>ifconfig eth0 192.168.181.115 netmask 255.255.0.0 broadcast 192.168.1.255

Changing ur MAC address

ifconfig eth0 down 
ifconfig eth0 hw ether 00:11:22:33:44:55 
ifconfig eth0 up

Print all the files names in a directory

# This will print the name of the files
for i in *; do echo "$i";done
# you can fix the top command to do more stuff. 
for i in *; do echo "ls -la $i";done
# if you want to execute a command on a files lines do the follow
for i in `cat SomeFile`;do echo "this line: $i ";done
# This will iterate through the lines and download them using git clone   
for i in `cat SomeFile`;do git clone "$i";done

Change all files extensions to another one

# This code will change all the {*.mp4.jpeg} into {*.jpeg}
for file in *.mp4.jpeg; do mv "$file" "${file%.mp4.jpeg}.jpeg"; done
# this another example 
for file in *.txt; do mv "$file" "${file%.txt}.py"; done

file	Load the crontab data from the specified file. If file is a dash ("-"), the crontab data is read from standard input.
-u user	Specifies the user whose crontab is to be viewed or modified. If this option is not given, crontab opens the crontab of the user who ran crontab. Note: using su to switch users can confuse crontab, so if you are running it inside of su, always use the -u option to avoid ambiguity.
-l	Display the current crontab.
-r	Remove the current crontab.
-e	Edit the current crontab, using the editor specified in the environment variable VISUAL or EDITOR.
-i	Same as -r, but gives the user a yes/no confirmation prompt before removing the crontab.
-s	SELinux only: appends the current SELinux security context string as an MLS_LEVEL setting to the crontab file before editing or replacement occurs. See your SELinux documentation for detailed information.

Installing Nginx & php on Ubuntu 22.04

sudo apt install nginx
# make sure it is enabled and started
sudo systemctl enable nginx 
sudo systemctl start nginx 
# this should result in active service.
sudo systemctl status nginx

sudo apt install php8.1-fpm  -y
# Make sure that the php is runing 
sudo systemctl status php8.1-fpm
# ------- [[ if you see this error ]] -------
#E: Unable to locate package php8.1-fpm
#E: Couldn't find any package by glob 'php8.1-fpm'
#E: Couldn't find any package by regex 'php8.1-fpm'
# do the following 
sudo apt update && apt install -y software-properties-common 
sudo add-apt-repository ppa:ondrej/php 
sudo apt update 
# and try after that
sudo apt install php8.1-fpm  -y
# --------------------------------------------
# direect to this folder 
cd /etc/nginx/site-available 
nano default 
# Add index.php to the list if you are using PHP
index index.php index.html index.htm index.nginx-debian.html;
# un-comment these lines of codes in this function 
# pass PHP scripts to FastCGI server
        #
        location ~ \.php$ {
                include snippets/fastcgi-php.conf;
        # ======= [[ MAKE SURE TO CHANGE THE VERSION TO MATCH YOURS 8.1 ]] ====
        #       # With php-fpm (or other unix sockets):
                fastcgi_pass unix:/run/php/php8.1-fpm.sock;
        #       # With php-cgi (or other tcp sockets):
        #       fastcgi_pass 127.0.0.1:9000;
        }
# un-comment this function 
location ~ /\.ht {
                deny all;
        }


# to validate the nginx configuration 
sudo nginx -t 

# Make a file in /var/www/html called index.php
<?php phpinfo();?>

# To check that php8.1-fpm is working do 
sudo systemctl status php8.1-fpm

checksec tinyshell

LDD command in Linux

check is an executable binary file needs shared object dependencies.

There are two types of libraries:

Static libraries
Dynamic or Shared Libraries

#To show the shared library dependencies of the bash binary,
sudo ldd /bin/bash

The above command shows the dependencies as:

Opemconnect

VPN client for Linux like anyconnect by cisco

# Install 
sudo apt install openconnect -y
# Connect to the vpn
sudo openconnect -u username -b vpn.server.com
# Check if it change your ip address using 
ip a 
# Disconnect 
sudo kill -9 $(pgrep openconnect | awk '{print $1}')

Really powerful word search

# search for a word "minmatch" inside codeql folder and print where it is found
find codeql -type f -exec grep minimatch {} \;
find codeql -type f -exec grep minimatch {} /dev/null \;

loocal machine :

71.230.187.109

Linux commands

Linux Useful Commands

Install any software on Linux

Search for a text in a directory or a folder

Start a service in Linux

Show the IPv4 address you got:

How to get a directory downloaded from a URL using wget

Find and delete duplicate files using fdupes

Return the public ip address of a machine

Change a mode of a wifi adapter to be monitored

Changing the MAC of your machine

Logging out a user using ssh (log out from all sessions)

Packet Sniffing on monitor mode adapter [Airodump-ng]

Know who is currently logged in your machine

Know the last modified files in a directory

Storing bash command and execute it by its name

Generate random MAC address:

Check the OS version you are using

Find all hard drive connected to the machine

To check linux architecture [arm,amd,etc]

How to read Hexdump formate file

Hash sha1 a folder or a directory

Change MAC address

Check the CPU type

Check Memory

Remove the cache or clear the cache

Downloading directory using Wget

Check CPU

Check wireless adapter

show a list of all Mac addresses table

show routing table of your machine

List all the apps installed in Linux

Firewall:

Remove a user from a group:

Find the largest folders in size on a directory

Find the largest files in size in a directory

Change Hostname on Ubuntu 20.04 (No Reboot Required)

How to ssh without ip (using domain name)

To change username and user's groupname (it is probably best to do this without being logged in):

Step 1: Use set-hostname to Change the Hostname

Step 2: Use hostnamectl to Confirm the Change

Add a user

Generate random password

Delete or Remove user

Check that you have sudo right

To check if user is been added

Check your username

Switch to user or change to user

Show or Display all groups:

disk free size, file management:

List all disks on linux

Linux crontab command

'crontab' in Linux with Examples - GeeksforGeeks

Change the IP of an UBUNTU server (Configure static IP):

Show the routing packet takes in your network

Show the default gateway IP address

Install MySQL server:

Change between users:

Change user to root:

See files sizes on current directory:

Find a move files that match the filter

Remove a single file, delete a file:

Remove files with prompting configuration:

Remove all files with the same extinctions, delete files :

Print with color in bash

Reset

Echo in color

Check the services running

Add script to run when reboot, run a script when startup, startup script: (crontab)

Install Apache server

See all processes currently running:

See the routing table (Netstat):

SSH:

Start / enable SSH server

SSH config file:

How to SSH without a password

Nmap

Access all server files locally, share access files on the server (sshfs)

Open Jupyter notebook from terminal

Numerical Base Conversions

Find and delete duplicate files using `fdupes`