Bash Cheatsheet.md

Bash Cheatsheet

The following is a list of various Bash commands which I use on a regular basis. It's not exhaustive, just a simple "getting started", and collection of useful commands. Anything between the brackets "<>" should be replaced.

Collection of various Bash commands:

• Bash One-liners
• Bash Scripting Cheatsheet
• apt-get aptitude cheatsheet
• aws cli cheatsheet
• postgres cheatsheet

Files

list files

ls

list all files

ls -la

create file

touch <file_name>

rename file

mv <file_name> <new_file_name>

copy file

cp <file_name> <file_name>

delete file

rm -f <file_name>

print file contents

cat <file_name>

scroll long file

less <file_name>

print first N lines

head -<n_lines> <file_name>

print last N lines

tail -<n_lines> <file_name>

search for filename's location

locate <file_name>

search for program's location

which <program_name>

search for a file, containing a string

find . -type f -print0 | xargs -0 grep "<search_string>"

Folders

show current folder

pwd

list sub-folders

ls -d */

change directory

cd <directory_name>

change to home folder

cd ~

create folder

mkdir <folder_name>

rename folder

mv <folder_name> <new_folder_name>

delete folder

rmdir <folder_name>

File / Folder Permissions

list permissions

ls -la

set executable

chmod +x <file_name>

set ownership

chown -R <user_name> <folder_name>

Environmental Variables

print existing variables

printenv

set variable

export VAR_NAME="hello"

print variable

echo $VAR_NAME

remove variable

unset VAR_NAME

Scripting

set script to be executable

chmod +x ./script_name.sh

set the executable flag on all .sh files

find ./ -name "*.sh" -exec chmod +x {} \;

run script

./script_name.sh

run script, but keep environmental variables

. ./script_name.sh
source ./script_name.sh

associative arrays

@see http://www.artificialworlds.net/blog/2012/10/17/bash-associative-array-examples/

Networking

list network adapters (Debian, Ubuntu, Kali)

ifconfig -a

list network adapters (Redhat, Fedora, CentOS)

ip link show

flush dns cache (Debian, Ubuntu, Kali Linux)

sudo /etc/init.d/dns-clean

restart networking (Debian, Ubuntu, Kali Linux)

sudo service network-manager restart

list all open ports

sudo netstat -tunlp

nmap <127.0.0.1 | localhost | ip_addr>

find if specific port is open

sudo netstat -tunlp | grep <port_number>

list all available hosts, within an ip range

nmap -sP 192.168.1.1/24

nmap -sP <ip_addr>/<ip_mask>

list all available hosts, within an ip range, on specific ports

# custom TCP SYN scan
sudo nmap -sP -PS22,3389 192.168.1.1/24
sudo nmap -sP -PS<port_1>,<port_2> <ip_addr>/<ip_mask>

#custom UDP scan
sudo nmap -sP -PU161 192.168.1.1/24
sudo nmap -sP -PU<port_1> <ip_addr>/<ip_mask>

SSH commands

connect

ssh <user_name>@<host_name>

connect, on specific port

ssh -p <port_number> <user_name>@<host_name>

connect, using keyfile

ssh -i <identity_filename> <user_name>@<host_name>

remove ssh key

ssh-keygen -R <server_dns> > /dev/null 2>&1;

copy remote file to local

scp <user_name>@<server_dns>:<remote_location> <local_location>

Hardware

http://www.haifux.org/lectures/86-sil/kernel-modules-drivers/kernel-modules-drivers.html

list all PCI system devices

lspci

list all running kernel modules

lsmod