To view the status of all print queues:

lpc status

To check the status of a single print queue and view a list of pending jobs:

lpc status lp1
lpstat -P lp1
lpstat -plp1

To remove a single print job:

cancel lp1-1234

To remove all print jobs in a queue:

cancel -a lp1

To enable  a queue:

cupsenable lp1

To disable a queue:

cupsdisable lp1

To enable all queues:

lpstat -p | grep disabled | awk '{print $2}' | xargs cupsenable

To print a test job:

echo test | lpr -P lp1

To restart/refresh the cups service:

service cups restart