portOpenCheck.bash

#!/usr/bin/env bash

START=$(date +%s.%N)

arg1=${1:-''}

if [[ $arg1 == '--help' || $arg1 == '-h' ]]; then
    echo "Use to test if port is open.  Requires a config file at $configFile with a list of '\$host/\$port', like"
    echo "lusk/22"
    echo "galaxy/22"
    echo "localhost/80"
    exit 0
fi


#exit when command fails (use || true when a command can fail)
set -o errexit

#exit when your script tries to use undeclared variables
set -o nounset

# in scripts to catch mysqldump fails
set -o pipefail

# Resolve first directory of script
PRG="$BASH_SOURCE"
progname=`basename "$BASH_SOURCE"`

while [ -h "$PRG" ] ; do
    ls=`ls -ld "$PRG"`
    link=`expr "$ls" : '.*-> \(.*\)$'`
    if expr "$link" : '/.*' > /dev/null; then
        PRG="$link"
    else
        PRG=`dirname "$PRG"`"/$link"
    fi
done

__dir=$(dirname "$PRG")


# Set magic variables for current file & dir
__root="$(cd "$(dirname "${__dir}")" && pwd)"           # Dir of the dir of the script
__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"       # Full path of the script
__base="$(basename ${__file})"                          # Name of the script
ts=`date +'%Y%m%d-%H%M%S'`
ds=`date +'%Y%m%d'`
pid=`ps -ef | grep ${__base} | grep -v 'vi ' | head -n1 |  awk ' {print $2;} '`
formerDir=`pwd`

# If you require named arguments, see
# http://stackoverflow.com/questions/192249/how-do-i-parse-command-line-arguments-in-bash

#=== BEGIN Unique instance ============================================
#Ensure only one copy is running
pidfile=$HOME/.${__base}.pid
if [ -f ${pidfile} ]; then
   #verify if the process is actually still running under this pid
   oldpid=`cat ${pidfile}`
   result=`ps -ef | grep ${oldpid} | grep ${__base} || true`

   if [ -n "${result}" ]; then
     echo "Script already running! Exiting"
     exit 255
   fi
fi

#grab pid of this process and update the pid file with it
echo ${pid} > ${pidfile}

# Create trap for lock file in case it fails
trap "rm -f $pidfile" INT QUIT TERM ERR
#=== END Unique instance ============================================


#Capture everything to log
mkdir -p ~/log
log=~/log/$__base-${ts}.log
exec >  >(tee -a $log)
exec 2> >(tee -a $log >&2)
touch $log
chmod 600 $log

#Set the config file
configFile="$HOME/.${__base}.conf"

#Check that the config file exists
if [[ ! -f "$configFile" ]] ; then
    echo "I need a file at $configFile with a list of '\$host/\$port', like"
    echo "lusk/22"
    echo "galaxy/22"
    echo "localhost/80"
        exit 1
else
    chmod 600 $configFile
fi

export DISPLAY=:0

### BEGIN SCRIPT ###############################################################

#(a.k.a set -x) to trace what gets executed
#set -o xtrace

for coords in `cat $configFile`; do
    error=1
    exec 6<>/dev/tcp/$coords && error=0
    exec 6>&- # close output connection
    exec 6<&- # close input connection

    if [[ "$error" -ne 0 ]]; then
    	echo "Nothing listening at $coords "
        exit $error
    else
        echo "OK: $coords"
    fi

done


set +x

### END SCIPT ##################################################################

cd $formerDir

END=$(date +%s.%N)
DIFF=$(echo "($END - $START)" | bc)
#echo Done.  `date` - $DIFF seconds

#=== BEGIN Unique instance ============================================
if [ -f ${pidfile} ]; then
    rm ${pidfile}
fi
#=== END Unique instance ============================================