Thank you very much guys..I tried your advise but i got the below..
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/http_core.py to http_core.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/http.py to http.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/client.py to client.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/http_interface.py to http_interface.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/service.py to service.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/__init__.py to __init__.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/atom/mock_http.py to mock_http.pyc
running install_egg_info
Writing /usr/local/lib/python2.7/dist-packages/gdata-2.0.17.egg-info
root@sark-HP-Pavilion-dv6-Notebook-PC:/opt/openerp/gdata-2.0.17# exit
exit
sark@sark-HP-Pavilion-dv6-Notebook-PC:/opt/openerp$ sudo su nautilus /opt/openerp
No passwd entry for user 'nautilus'
sark@sark-HP-Pavilion-dv6-Notebook-PC:/opt/openerp$ git clone https://github.com/odoo/odoo.git --branch 8.0
fatal: could not create work tree dir 'odoo'.: Permission denied
sark@sark-HP-Pavilion-dv6-Notebook-PC:/opt/openerp$