uptest.sh

#!/usr/bin/env bash
if [ x$BASH = x ] || [ ! $BASH_VERSINFO ] || [ $BASH_VERSINFO -lt 3 ]; then
  echo "Error: Must use bash version 3+." >&2
  exit 1
fi
Silence="$HOME/.local/share/nbsdata/SILENCE"
SleepDefault=5
LogfileDefault="$HOME/.local/share/nbsdata/uptest.log"
TimeoutDefault=4
Usage="Usage: $(basename $0) [sleep seconds [-l [log]]]
  e.g. $(basename $0) 10 -l log.txt
sleep seconds: Optional, default is $SleepDefault seconds.
-l: Optional, default is no logging. Sleep seconds must be given if -l is.
    If -l is given alone, it will log to the default file:
    $LogfileDefault
    If a filename is given after -l, it will log to that file.
    If silence file named "$Silence" exists, it will stop
    logging until it is gone."

# Read arguments.
sleep=$SleepDefault
logfile=$LogfileDefault
timeout=$TimeoutDefault
if [[ "$1" ]]; then
  if [[ "$1" =~ ^[0-9]+$ ]]; then
    sleep="$1"
  else
    echo "$Usage"
    exit 1
  fi
fi
if [[ "$2" ]] && [[ "$2" == "-l" ]]; then
  log="true"
  if [[ "$3" ]]; then
    logfile="$3"
  fi
  echo "Logging to file $logfile"
fi

# Is it the BSD version of ping?
bsd=''
version=$(ping -V 2>/dev/null)
if ! echo $version | grep -qF iputils; then
  kernel=$(uname -s | tr '[:upper:]' '[:lower:]')
  if [[ $kernel == darwin ]] || [[ $kernel =~ bsd$ ]]; then
    bsd='true'
  fi
fi
# If it's the BSD version, -W is in milliseconds.
if [[ $bsd ]]; then
  timeout=$((timeout*1000))
fi

while [[ 1 ]]; do
  last=$(date +%s)
  sleeptime=$sleep
  if [[ -f "$Silence" ]]; then
    echo "Silence file $Silence exists. Skipping ping.."
    sleep $sleeptime
    continue
  fi
  humantime=$(date '+%Y-%m-%d %H:%M:%S')
  response=$(ping -n -c 1 -W $timeout google.com 2>/dev/null | grep 'bytes from')
  # todo: decide success based on the summary line ("1 received")
  if [[ ${#response} -gt 0 ]]; then
    dest=$(echo $response | sed -E 's/^.* from ([0-9]+\.[0-9]+\.[0-9]+\.[0-9]+): .*$/\1/')
    ms=$(echo $response | sed -E 's/^[0-9]+ bytes from [0-9.]+:.* time=([0-9.]+) ms.*$/\1/')
    if [[ ! $ms =~ [0-9.]{1,6} ]]; then
      echo -e "Error: time regex failed to match line:\n$response" 1>&2
      ms=0
    fi
    result="$ms ms\tfrom $dest"
    logline="$ms\t$last"
  else
    result="**********DROPPED**********"
    logline="0\t$last"
    #sleeptime=5
  fi
  
  now=$(date +%s)
  elapsed=$((now - last))
  ratio=$((elapsed/sleeptime))
  #echo -n "start: $elapsed "
  if [[ $ratio -eq 0 ]]; then
    ratio=1
  fi
  while [[ $ratio -gt 0 ]]; do
    echo -ne "$result\t$humantime\t"
    if [[ "$log" ]]; then
      echo -e "$logline" >> "$logfile"
    fi
    ratio=$((ratio-1))
    if [[ $ratio -gt 0 ]]; then
      echo
    fi
  done

  while [[ $elapsed -lt $sleeptime ]]; do
    echo -n '*'
    sleep 1
    now=$(date +%s)
    elapsed=$((now - last))
  done
  echo -ne "\n"
done