What is a sticky Bit and how to set it in Linux

Sticky bits are mainly set on directories.

If you give 777 (full permission) to any directory then all users can delete,modify all files and directories so to avoid this we use sticky bit. by using it, all users can create and modify their own directories or files not others 

If the sticky bit is set for a directory, only the owner of that directory or the owner of a file can delete or rename a file within that directory.

The following two commands are used  to apply sticky bit on any directory  

chmod +t directory_name 
OR 
chmod 1777 directory_name

Example:
Consider you have a directory "sticky ".

drwxr-xr-x    2 user1 user1  4096 Jul 10 12:07 sticky

chmod it to " 777 ". This gives permissions for all the users to read, write and execute.

as: #chmod 777 /sticky/

then check 

drwxrwxrwx    2  user1 user1  4096 Jul 10 12:07 sticky

Then Apply Sticky bit

drwxrwxrwt    2 root root  4096 Jul 10 12:07 sticky

From the above example user1 is the owner of the sticky directory. then create some files and folders and check 

-rw-rw-r-- 1  user2 user2 0 Jul 10 12:26 test2

-rw-rw-r-- 1 user4 user4 0 Jul 10 12:27 test3

user2 can delete or modify only file test2
user4 can delete or modify only file test3