Bash script to monitor internet outages

netwatch.sh

# return 1 if alive, 0 if dead
ping_success() {
  ! ping -c1 -W1 8.8.8.8 >/dev/null 2>&1
}

# Spinner taken from https://stackoverflow.com/a/12498395
spinnerindex=0
spinner='-\|/'
sleepy_spinner() {
  for (( i=0; i<$(($1 * 2)); i++ ))
  do
    spinnerindex=$(( (i+1) %4 ))
    printf "\r${spinner:$spinnerindex:1} $2"
    sleep 0.5
  done
}

downstart=$(date +%s);
downend=$(date +%s);
downcount=0
internetstatus=1
 
while [ 1 ]; do
  (ping_success)
  pingresult=$?
 
  if ((pingresult==0)) && ((internetstatus==1)); then
    ((internetstatus=0))
    ((downcount++))
    downstart=$(date +%s);
    dt=$(date +%Y-%m-%d" "%H:%M:%S);

    printf "\r$dt Internet went down #$downcount\n"
  elif ((pingresult==1)) && ((internetstatus==0)); then
    ((internetstatus=1))
    downend=$(date +%s);
    dt=$(date +%Y-%m-%d" "%H:%M:%S);
    downseconds=$(( ($downstart - $downend) * -1 ))
    if ((downseconds < 60)); then
      printf "\r$dt Internet alive after being offline for $downseconds seconds\n"
    else
      downminutes=$(( $downseconds / 60 ))
      printf "\r$dt Internet alive after being offline for $downminutes minutes\n"
    fi
  fi 

  # Spin spinner so the user knows we're alive
  if ((internetstatus==1)); then
    (sleepy_spinner 15 "Online")
  else
    (sleepy_spinner 5 "No connection")
  fi
done