help()
{
  header
  echo
  echo 'Usage: cckiller [OPTIONS] [N]'
  echo 'N : number of tcp/udp connections (default 100)'
  echo
  echo 'OPTIONS:'
  echo "-h | --help: Show this help screen"
  echo "-k | --kill: Block the offending ip making more than N connections"
  echo '-s | --show: Show The TOP "N" Connections of System Current'
  echo "-b | --banip: Ban The IP or IP subnet like cckiller -b 192.168.1.1"
  echo "-u | --unban: Unban The IP or IP subnet which is in the BlackList of iptables"
  echo
}
if [ $# -lt 2 ]; then
  help
fi

# Notes:
#  - Please install "jq" package before using this driver.
usage() {
  err "Invalid usage. Usage: "
  err "\t$0 init"
  err "\t$0 mount <mount dir> <json params>"
  err "\t$0 unmount <mount dir>"
  exit 1
}
err() {
  echo -ne $* 1>&2
}
...
if [ $# -lt 2 ]; then
  usage
fi
....