Simple Bash Scripting Cheatsheet

[+] nano Shortcuts ctrl v Next page. ctrl y Previous page. ctrl w Where is (find). ctrl k Cut that line of test. ctrl x Exit editor.

[+] Create a text file: touch file Creates an empty file. ifconfig > tmp pipe the output of a command nano file

[+] Create a file and append text to it: ifconfig > tmp
echo >> tmp ping google.com -c3 >> tmp

[+] How to view a file: cat file Show entire contents of file. more file Show one page at a time. Space bar for next page and (q) to exit. head file Show the first 10 lines. head -15 file Show the first 15 lines. tail file Show the last 10 lines. tail -15 file Show the last 15 lines. tail -f file Useful when viewing the output of a log file.

[+] pipe cat tmp | grep Bcast Feeds the output of one process to the input of another process.

[+] Processes ps aux Show all running process for all users. kill -9 PID Nicely kill a PID.

[+] Word Count wc -l tmp2 Count the number of lines in a file

[+] cut -d delimiter -f fields

[+] sort Sort by unique sort -u file sort IP addresses correct sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n cat tmp2 | cut -d '(' -f2 | cut -d ')' -f1 | sort -u Isolate the IP address

[+] awk awk '{print $1}' file Show the 1st column. awk '{print $1,$5}' file Show the 1st and 5th columns.

[+] grep grep -v Remove a single string. grep -v 'red' file

[+] egrep -v Remove multiple strings egrep -v '(red|white|blue)' file

[+] sed sed 's/FOO/BAR/g' file Replace FOO with BAR. sed 's/FOO//g' file Replace FOO with nothing. sed '/^FOO/d' file Remove lines that start with FOO.

[+] colour 31=red 32=green 33=yellow 34=blue 35=magenta 36=cyan echo -e "\e[1;34mThis is a blue text.\e[0m"

Bash Scripts

[+] Simple bash script:

!/bin/bash

clear echo echo print "Hello world."

[+] Make a file executable. chmod +x file chmod 755 file

[+] Variables name=Bob echo $name user=$(whoami) echo $user echo 'Hello' $name. 'You are running as' $user.

!/bin/bash

clear echo "Hello World" name=Bob ip=ifconfig | grep "Bcast:" | cut -d":" -f2 | cut -d" " -f1 echo "Hello" $name "Your IP address is:" $ip

[+] User Input read -p "Domain: " domain

!/bin/bash

echo "Please input your domain:" read -p "Domain:" domain ping -c 5 $domain

[+] Check For No User Input if [ -z $domain ]; then echo echo "#########################" echo echo "Invalid choice." echo exit fi

[+] For loops

!/bin/bash

for host in $(cat hosts.txt) do command $host done

[+] One Liners

Port Scan: for port in $(cat Ports.txt); do nc -nzv 192.168.0.1 $port & sleep 0.5; done

Use a bash loop to find the IP address behind each host: for url in $(cat list.txt); do host $url; done

[+] Condition Onliner

any command && if work || if not work type -p massdns && massdns -r resolver.txt -t A -o S sub.txt -w sub.mass || echo "MassDns not installed"

[+] Condition Onliner with multiple action

any command && { if work; also this; also this } || { if not work; also this; also this } type -p massdns && { massdns -r resolver.txt -t A -o S sub.txt -w sub.mass; cat sub.mass } || { echo "MassDns not installed"; echo "Install MassDns" }