View which applications use port tcp 80

lsof -i tcp:80

View application network activity

lsof -i

View files larger than 1GB

find / -type f -size +1G

View HTTP headers on shell

curl -I http://www.google.com.tr

View all permission 777 files

find / -perm 777

View website source on shell

curl -L http://www.google.com

View your external IP on shell

curl ip.appspot.com

Hello World !

 :)