#!/bin/bash

progname=${0##*/}
die() {
    printf >&2 '%s ERROR: %s\n' "$progname" "$*"
    exit 1
}

read -rsp 'Password: ' pass >&2
printf >&2 '\r\e[K'

exec {zmin}<> <(:)
exec {zmout}< <(
    script -f /dev/null -c '
	ssh -oPubkeyAcceptedAlgorithms=+ssh-rsa \
		-oHostKeyAlgorithms=+ssh-dss admin@zmodem
	' 2>&1 <&$zmin
)
IFS= read -d : -u $zmout -t 3 line || die "Can't connect."

echo >&$zmin "$pass"
IFS= read -d \> -u $zmout -t 3 _ || die "No prompt line." # Zyxel prompt: ZySH>

getPppStat() {
    echo >&$zmin 'ifconfig | grep "ppp\|RX b"'
    while read -u $zmout -t .2 line;do
	  case $line in
	      RX* | ifconfig* ) ;;
	      ppp* )
		  IFS=': ' read -ru $zmout -t 1 _ _ rx _ _ _ _ tx _
		  break
		  ;;
       	      * ) echo $line;;
	  esac
    done
	  IFS= read -d \> -u $zmout -t 3 _ || die "No prompt line."
}

start=${EPOCHREALTIME/.}
getPppStat
elap=00000$(( ${EPOCHREALTIME/.} - start ))
printf '%7.4f %s %s\n' ${elap::-6}.${elap: -6} ${rx@A} ${tx@A}
orx=${rx} otx=${tx}
sleep 2
start2=${EPOCHREALTIME/.}
getPppStat
elap=00000$(( ${EPOCHREALTIME/.} - start2 ))
printf '%7.4f %s %s\n' ${elap::-6}.${elap: -6} ${rx@A} ${tx@A}

echo $(( start2 - start )) $(( rx - orx )) $(( tx - otx ))

echo >&$zmin 'exit'
while read -u $zmout -t .3 line; do
      : # echo $line  
done