Adding package repository sources to source list in ubuntu

To add sources to source list we can follow either Terminal mode Or from the GUI mode we can add sources to source.list file.
I will describe both the ways....
From Terminal:
# At first open the terminal [ Application>>Accessories>>Terminal ]
# Then write the following command on the terminal [Except the "" marks]
" sudo gedit /etc/apt/sources.list "
# If required provide the sudo password or your user password.
# Then a new window will open.
# In that window at last of that window just add your sourcess and save the file and close. You are done.
# Now write " sudo apt-get update " in the terminal.
Now it is updated.


From GUI Mode:
To add sources from GUI mode,
#Click on System>>Administration>>Software sources.
#If required give ur sudo password.
#A new window will come , in that window select Third party software tab and at the bottom left corner u will get an ADD button. Click on that, A text box will appear and paste your source there and press ok.
#Now close the window and u will be prompted to update ur aptitude list. click ok there. You are done.