FRATE - Print file grow rate in Kbps

frate.sh

#! /bin/sh

# FRATE - Print file grow rate in Kbps
# Copyright (C) 2012 Matous J. Fialka, <http://mjf.cz/>
# Released under the terms of The MIT License

if [ $# -ne 1 ]
then
        printf 'usage: frate [file]\n' 1>&2
        exit 1
fi

CURRENT=`stat -c %s $1`
LAST=0
RATE=0

while :
do
        LAST=$CURRENT
        CURRENT=`stat -c %s $1`
        RATE=$((((CURRENT-LAST)/1024)*8))

        printf '% 9d Kbps\b\b\b\b\b\b\b\b\b\b\b\b\b\b' $RATE

        sleep 1
done