Hello Yakito,
First thing you need to do is stoping the server by finding the process use command
sudo ps -aux | grep openerp-server
then in the output you will have process id after the username.
software 4761 9.2 1.7 131124 69256 pts/10 Sl 11:04 0:04 python openerp-server
software 4776 0.0 0.0 4680 800 pts/10 S+ 11:04 0:00 grep --color=auto openerp-server
here 4761 is the Process id and need to kill the process
using this command
sudo kill -9 4761
Now we will see the different way to start server and stoping it in a easy way. Killing processes as above is not good for computer health.
Option 1 :
You can start the OpenERP server without "&" sign.
It will run in terminal and you can see the logs over there.
on pressing of "Ctrl+C", It will stop the server and you can start again the server by just "/opt/odoo/openerp-server" command.
Option 2 :
You can start the odoo server by
cd /opt/odoo/
./odoo.py
or you can start it by
python /opt/odoo/odoo.py
After all this when you want to stop the server, Simply just press "Ctrl+C".
Regards,
Hardik