Reset PRAM in Mac OS without holding keys at startup

This command is the functional equivalent of holding down command-option-p-r at start up.  It resets the machine's PRAM. 

% sudo nvram boot-args='-p -r'

My 2009 Mac mini was having problems starting up (light on but no ding or gray apple screen).  I have not seen this startup problem since resetting the PRAM.  Hopefully this fixes the problem.