block websites without using any software

This is very easy to block website you have to do only small changes in the "hosts" file with is present in the

"C:\Windows\System32\drivers\etc" pasth.(Windows)

Step 1:

Open host file and add this line to the end of the file "127.0.0.1           example.com" . example.com is the website name you want to block.

Step 2:

type all the possible way to write the website for example.

127.0.0.1           example.com

127.0.0.1           www.example.com

127.0.0.1           http://example.com

127.0.0.1           http://www.example.com

127.0.0.1           http://example.com

127.0.0.1           https://www.example.com

Step 3:

save the file. (some time file is not able to save then save as that file on desktop and cut it from desktop and paste into "C:\Windows\System32\drivers\etc" directory)

OR you can make software to block website using this method in c++,java by Using file input ,output stream.

simple linux commands basic

Linux commands :

1.add user in linux
useradd user_name

2.change password
passwd user_name

3.removing user/group
userdel/groupdel user_name/group_name

4.show all process
  ps 

5. Delete  running process
kill p_id    ( -9 for force quit )

6.Show user details 
 id user_name

7.How to find particular word in file

grep "find_String" file_name
egrup -r "s1|s2" file_name

8.show open ports in linux
netstat --listen OR netstat

9.show how many file are open
lsof

10.memory status
 free

How to run Firefox os on pc(Using firefox browser)

Now you can run run Firefox os simulator on your pc

Step 1:

Download and install Firefox browser 

Step 2:

Open this link into firefox browser https://addons.mozilla.org/en-US/firefox/addon/firefox-os-simulator/

and click on the "Add to firefox".

Step 3:

After adding addon to the firefox go to "Firefox >> Web Developer >> Firefox os simulator"

Step 4:

Click on "Stopped ".

Step 5:

Now simulator is ready to use.