Ping a Host & Save Status to Log File

ping.sh

#!/bin/bash

STAMP=`date "+%y%m%d-%H:%M:%S"`
FILE="/var/log/ping.log"
ISUP="DOWN"

_update () {
  if [ ! -f "$FILE" ]; then
    echo "$STAMP $ISUP" > $FILE
  fi
  
  LAST=$( tail -n 1 $FILE )

  if [[ $LAST == *"$ISUP"* ]]; then
    echo "No Change: $ISUP"
  else
    echo "Changed: $ISUP";
    echo "$STAMP $ISUP" >> $FILE  
  fi
  
}

_ping () {
  
  ping -c1 $1 > /dev/null
  if [ $? -eq 0 ]
    then 
      echo ok
      ISUP="UP"
    else
      echo "fail"
      ISUP="DOWN"
  fi
}

_ping $1;
_update;
cat $FILE;