Q:

sudo apache2 stop doesn't work

not sure why but when I run:
ubuntu@ip-10-46-206-16:/etc/init.d$ sudo apache2 stop
Usage: apache2 [-D name] [-d directory] [-f file]
               [-C "directive"] [-c "directive"]
               [-k start|restart|graceful|graceful-stop|stop]
               [-v] [-V] [-h] [-l] [-L] [-t] [-S] [-X]
Options:
  -D name            : define a name for use in <IfDefine name> directives
  -d directory       : specify an alternate initial ServerRoot
  -f file            : specify an alternate ServerConfigFile
  -C "directive"     : process directive before reading config files
  -c "directive"     : process directive after reading config files
  -e level           : show startup errors of level (see LogLevel)
  -E file            : log startup errors to file
  -v                 : show version number
  -V                 : show compile settings
  -h                 : list available command line options (this page)
  -l                 : list compiled in modules
  -L                 : list available configuration directives
  -t -D DUMP_VHOSTS  : show parsed settings (currently only vhost settings)
  -S                 : a synonym for -t -D DUMP_VHOSTS
  -t -D DUMP_MODULES : show all loaded modules 
  -M                 : a synonym for -t -D DUMP_MODULES
  -t                 : run syntax check for config files
  -X                 : debug mode (only one worker, do not detach)

it doesn't seem to stop the server. I still trying to ping the ip and it's returning the default page. Is there a reason why?

A:

Try:
 sudo service apache2 stop

See here:

https://help.ubuntu.com/community/ApacheMySQLPHP

The older way would be:
sudo /etc/init.d/apache2 stop

Note that when you do sudo apache2 stop, you are running apache2 from you PATH, not from the current folder (usually, . is not in the PATH). Try sudo ./apache2 stop for that.
See here:

http://www.cyberciti.biz/faq/ubuntu-linux-start-restart-stop-apache-web-server/

