Run command line no wait and no output

You can write the command like this:

long-running-command &

The ampersand in the end of this command tells this command will be executed in the background. You can press Ctrl+Z to suspend the command, and then bg to put it in the background if you want.

To suppress possible command output (command errors) try this:

long-running-command > /dev/null 2>&1 &

With the last line you will not get the standard output ( /dev/null ) and the errors will not show.