This will run both simultaneously.
# coffee -wc lib/ && coffee -wcb public/
UPDATE: As per Dennis and Neurolysis's comment, I'm changing the answer to use an &. Although both commands are similar, the && operator will cause the 2nd command to be run only after the first is completed.
## print 'program1', wait 4 seconds, print 'program2'
# echo 'program1';sleep 4 && echo 'program2'
## print 'program1' and sleep, but also simulatneously print 'program2'
# echo 'program1';sleep 4 & echo 'program2'
Thus, the technically correct answer is:
# coffee -wc lib/ & coffee -wcb public/