Run scripts on start up in Linux

There are different ways to automatically run commands:

1. The upstart system will execute all scripts from which it finds a configuration in directory /etc/init. These scripts will run during system startup (or in response to certain events, e.g., a shutdown request) and so are the place to run commands that do not interact with the user; all servers are started using this mechanism.

You can find a readable introduction to at: http://upstart.ubuntu.com/getting-started.html the man pages man 5 init and man 8 init give you the full details.

2. A shell script named .gnomerc in your home directory is automatically sourced each time you log in to a GNOME session. You can put arbitrary commands in there; environment variables that you set in this script will be seen by any program that you run in your session.

Note that the session does not start until the .gnomerc script is finished; therefore, if you want to autostart some long-running program, you need to append & to the program invocation, in order to detach it from the running shell.

3. The menu option System -> Preferences -> Startup Applications allows you to define what applications should be started when your graphical session starts (Ubuntu predefines quite some), and add or remove them to your taste. This has almost the same purpose and scope of the .gnomerc script, except you don't need to know sh syntax (but neither can you use any shprogramming construct).

 4. One approach is to add an @reboot cron task:

Running crontab -e will allow you to edit your cron.

Adding a line like this to it:

@reboot /path/to/script

will execute that script once your computer boots up.