The process to continually run a command is in the example below:
7100(su)->loop 10 60
show port flowcontrol <port-string>
show rmon stats <port-string>
10 = Specifies the number of times to loop.
A value of 0 will make the command loop forever
60 = Specifies the number of seconds to delay between executions.
in order to stop the command: CRTL + C