Show RAM and SWAP usage in a simple and pretty manner

#!/bin/sh

drawChart()
{
COUNT=0
MAX=30
CHARTWIDTH=`expr $MAX - 2`
CHARTUSED=`expr $2 '*' $MAX / $1`
CHARTFREE=`expr $CHARTWIDTH - $CHARTUSED`

echo -n "["
while [ $COUNT -lt $MAX ] ;
do
if [ $COUNT -lt $CHARTUSED ]; then
echo -n "#"
else
echo -n "."
fi
COUNT=`expr $COUNT + 1`
done
echo "] ($3% occupied)"
}

RAM=`free -m | grep Mem`
SWAP=`free -m | grep Swap`

RAMTOTAL=`echo $RAM | awk '{ print $2 }'`
RAMUSED=`echo $RAM | awk '{ print $3 }'`

SWAPTOTAL=`echo $SWAP | awk '{ print $2 }'`
SWAPUSED=`echo $SWAP | awk '{ print $3 }'`

RAMPERCENT=`expr 100 '*' $RAMUSED '/' $RAMTOTAL`
SWAPPERCENT=`expr 100 '*' $SWAPUSED '/' $SWAPTOTAL`

echo "RAM (total: $RAMTOTAL MB; used: $RAMUSED MB)"
drawChart $RAMTOTAL $RAMUSED $RAMPERCENT

echo

echo "SWAP (total: $SWAPTOTAL MB; used: $SWAPUSED MB)"
drawChart $SWAPTOTAL $SWAPUSED $SWAPPERCENT