Bash — [: too many arguments - bash

Question

#!/bin/bash
# portcheck tool
usage()
{
echo -e "\n USAGE: ./${0##*/} [host|ip] \n"
exit
}
check_port()
{
local host=${1}
local port=${2}
if [ nc -w 5 -z host port ] && [ nc -w 5 -z host port ]
then
echo -e "\a\n => Port ${port} at ${host} is open"
else
echo -e "\a\n => Port ${port} at ${host} is closed"
fi
}
[[ $# -ne 2 ]] && usage
check_port ${1} ${2}
When I run the following command:
bash portOpenBash.sh 127.0.0.1 434
I get the following error:
portOpenBash.sh: line 14: [: too many arguments
I try to put quotes between the macro expression, but I get the same error.

Answer 1

Problem seems to be in your if conditions here:
if [ nc -w 5 -z host port ] && [ nc -w 5 -z host port ]
You probably want to check for non empty output of both commands like this:
if [ -n "$(nc -w 5 -z $host $port)" ] && [ -n "$(nc -w 5 -z $host $port)" ]
OR in BASH:
if [[ -n "$(nc -w 5 -z $host $port)" && -n "$(nc -w 5 -z $host $port)" ]]
EDIT:
OR else if you just want to check return codes then remove surrounding [ and ]:
if nc -w 5 -z $host $port && nc -w 5 -z $host $port