nice

Run a command with modified priority.

Syntax
      nice [-n increment] Command [Arg]...

Key
   -n increment  A positive or negative decimal integer used
                 to modify the system scheduling priority of command

If an increment is given, it is used; otherwise an increment of 10 is assumed.

The super-user can run commands (utilities) with priorities higher than normal by using a negative increment.

The priority can be adjusted over a range of -20 (the highest) to 20 (the lowest).

Exit Status
1-125 An error occurred in the nice utility.
126 The command was found but could not be invoked.
127 The command could not be found.
Otherwise, the exit status of nice shall be that of command.

“Work is achieved by those employees who have not yet reached their level of incompetence” - Laurence J. Peter (The Peter Principle)

Related:

nice man page - Apple.com
nohup - Run a command immune to hangups
sleep - Delay for a specified time
getpriority
setpriority
renice