cat /etc/snort/snort.conf

nl /etc/snort.conf 

# example
tail -n+507 /etc/snort/snort.conf | head -n 6

sed s/mysql/MySQL/g /etc/snort/snort.conf > snort2.conf

curl https://ipinfo.io/ip

ifconfig
iwconfig

ifconfig eth0 192.168.181.115

ifconfig etho0 192.168.181.115 netmask 255.255.0.0 broadcast 192.168.1.255

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

dhclient etho

dig hackers-arise.com ns
dig hackers-arise.com mx
vim /etc/resolv.conf 
vim /etc/hosts

ss # new netstat
https://www.tecmint.com/ss-command-examples-in-linux/

ip addr show
ip route show
mtr baidu.com
printf 'HEAD / HTTP/1.1\r\nHost: www.baidu.com\r\n\r\n' | nc www.baidu.com

apt-cache search snort

cat /etc/apt/sources.list
deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main 
deb-src http://ppa.launchpad.net/weupd8team/java/ubuntu precise main

git clone https://www.github.com/balle/bluediving.git

compgen -u
less /etc/passwd

cut -d: -f1 /etc/passwd
getent passwd | awk -F:'{print $1}'

who
# The second column will give you what type of connection it is: if it’s represented with a “:X” where X is a number, it means it is using a Graphical User Interface (GUI) or Desktop session such as Gnome, XDE, etc; if it says “pts/X” where X is a number, it means it’s a connection made through SSH protocol (command line).

# list all cmd available
compgen -c

chown $user $file
chgrp $group $app

chmod 777 FILE
chmod u-w FILE # user minus write

find / -user root -perm -4000