add-apt-repository for adding repository in /etc/apt/sources.list

Adding repository in Debian and Ubuntu

We can add the repository url to the /etc/apt/sources.list using add-apt-repository

$ sudo apt-get install python-software-properties    ---------------> Package name

#### Package will be available in https://packages.debian.org/jessie/admin/python-software-properties

example adding the docker repository to the debian sources.list

$ sudo add-apt-repository  "deb https://apt.dockerproject.org/repo debian-$(lsb_release -cs)  main"

Notes
----------------------
$lsb_release -a

Output
-----------------------
-----------------------
### option -a --> All information

dev@ip-10-0-2-87:~# lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 8.6 (jessie)
Release:        8.6
Codename:       jessie


Options:
-c --> Get the code name of the currently installed distribution
----------------------------------------------------------------
Example:

root@ip-10-0-2-87:~# lsb_release -c
Codename:       jessie


-s --> Gives shot output format
---------------------------------
Example:

root@ip-10-0-2-87:~# lsb_release -cs
jessie   ----------------------------------------> Extract the code name of the distro