where to add that command line so that every time i boot up it is executed.
More info is needed on this one, if you have a command you want to run as a daemon with root privileges, add it to "/etc/rc.local" script. This script is the last script that runs just before the GUI show up when you boot
If you want the script to start up on login and to run with logged in user privileges, go to "system settings -> system administration -> start up and shut down -> autostart" and add your script here
rules of the forum demands one question per post.
You asked these questions and most likely somebody else will too sooner or later, having one question per thread and with a descriptive title will help a lot of those who will have the same questions but search first before re asking the questions. These rules are in place not to inconvenience you, but to make the forum more functional for you and those who will come after you who may seek answers to the same questions you have.