[turrini]

I've made a simple script based on your example:

wirelive.sh:

  #!/bin/bash
  
  if [[ -z "$1" ]]; then
      echo -e "Usage: $(basename $0) <host[:port]> <interface> [filters]"
      exit
  fi
  
  ssh_host=$(echo $1 | cut -d: -f1)
  ssh_port=$(echo $1 | cut -s -d: -f2)
  [[ -z "$ssh_port" ]] && ssh_port=22
  [[ -z "$2" ]] && tcpdump_interface="any" || tcpdump_interface="$2"
  [[ ! -z "$3" ]] && tcpdump_filters="and \($3\)"
  
  ssh root@${ssh_host} -p ${ssh_port} \
      tcpdump -U -s0 "not port ${ssh_port} ${tcpdump_filters}" -i ${tcpdump_interface} -w - \
      | wireshark -k -i -

[pstuart]

nice, but a small nit: you don't need to quote variables inside bash double brackets.