Block and Unblock a website on MAC

blockunblock.txt

Block a website ( www.facebook.com )
1. Open terminal
2. Enter following command - 
  sudo nano /etc/hosts
3. Enter MAC system password
4. Scroll down and make an entry for the website you wish to block - 
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1       localhost
255.255.255.255 broadcasthost
::1             localhost

127.0.0.1 www.facebook.com
127.0.0.1 facebook.com
127.0.0.1 www.fb.com
127.0.0.1 fb.com

5. Press Control(^) and X to Exit
6. Press Y fo yes to save the entry
7. Press Enter to come out of the file

To Verify - 
1. Clear Cache using the following command - 
  sudo dscacheutil -flushcache
2. Open Chrome (works for chrome) - Check the website (www.facebook.com)

( or )

1. Restart your computer
2. Open Chrome (works for chrome) - Check the website (www.facebook.com)

Done.
=============
UnBlock a website ( www.facebook.com )
1. Remove/Replace the site address from /etc/hosts