Shell脚本实现的单机流量统计功能

在网上看到这个单机流量的脚本，挺不错的。

代码如下:
#!/bin/sh
usage(){
echo “Usage: $0 [-i INTERFACE] [-s INTERVAL] [-c COUNT]”
echo
echo “-i INTERFACE”
echo “    The interface to monitor, default is eth0.”
echo “-s INTERVAL”
echo “    The time to wait in seconds between measurements, default is 3 seconds.”
echo “-c COUNT”
echo “    The number of times to measure, default is 10 times.”
exit 3
}
readargs(){
while [ "$#" -gt 0 ] ; do
  case “$1″ in
   -i)
    if [ "$2" ] ; then
     interface=”$2″
     shift ; shift
    else
     echo “Missing a value for $1.”
     echo
     shift
     usage
    fi
   ;;
   -s)
    if [ "$2" ] ; then
     sleep=”$2″
     shift ; shift
    else
     echo “Missing a value for $1.”
     echo
     shift
     usage
    fi
   ;;
   -c)
    if [ "$2" ] ; then
     counter=”$2″
     shift ; shift
    else
     echo “Missing a value for $1.”
     echo
     shift
     usage
    fi
   ;;
   *)
    echo “Unknown option $1.”
    echo
    shift
    usage
   ;;
  esac
done
}
checkargs(){
if [ ! "$interface" ] ; then
  interface=”eth0″
fi
if [ ! "$sleep" ] ; then
  sleep=”3″
fi
if [ ! "$counter" ] ; then
  counter=”10″
fi
}
printrxbytes(){
/sbin/ifconfig “$interface” | grep “RX bytes” | cut -d: -f2 | awk ‘{ print $1 }'
}
printtxbytes(){
/sbin/ifconfig “$interface” | grep “TX bytes” | cut -d: -f3 | awk ‘{ print $1 }'
}
bytestohumanreadable(){
multiplier=”0″
number=”$1″
while [ "$number" -ge 1024 ] ; do
  multiplier=$(($multiplier+1))
  number=$(($number/1024))
done
case “$multiplier” in
  1)
   echo “$number Kb”
  ;;
  2)
   echo “$number Mb”
  ;;
  3)
   echo “$number Gb”