nice
Run a command with modified priority. 
SYNTAX
      nice [+number] [Command [Arg]...]
      nice [-n number] Command [Arg]...
OPTION
      number    Scheduling priority.
                Priority can be adjusted over the range
                of -20 (the highest priority)*
                to 19 (the lowest=less cpu) 
	        The super-user may specify negative priority by using
	       `nice -number ...'.
If no arguments are given, `nice' sets the current scheduling priority for the shell to 4, or if number is given; priority is set to number.
If Command is given, `nice' runs the given Command 
  with its scheduling priority adjusted. 
  
  Command is always executed in a sub-shell, and the restrictions placed 
  on commands in simple if statements apply.
* check these figures
 Syntax shown above is; firstly the tcsh shell command `nice' 
  and the (very similar) external `nice' utility.
  
  "Work is achieved by those employees who have not yet reached their 
  level of incompetence" - Laurence J. Peter (The 
  Peter Principle) 
Related commands:
  
  nohup - Run a command immune to hangups
  sleep - Delay for a specified time 
  
  Equivalent BASH command:
  
  nice - Run a command with modified priority