oh no! progress monitoring in bash!

logmon.sh

#!/bin/bash

total_percent=3649.39

for i in {0..9}; do
        last_ten_line_counts[$i]=0
done

idx=0
while [ 1 ]; do 
        echo
        date 
        wc -l log/x* 
        lines=`grep 'key: ' log/x* | wc -l| awk '{ print $1 }'`
        echo
        percent=`echo "$lines / $total_percent " | bc -l`
        echo "$percent %"
        echo
        last_ten_line_counts[$idx]=$lines
        let ten_minutes_ago_idx=($idx+1)%10
        if [ "${last_ten_line_counts[$ten_minutes_ago_idx]}" -eq "0" ]; then
                echo "wait $(( 10 - $idx )) for progress per minute"
        else
                per_minute=`echo "(${last_ten_line_counts[$idx]} - ${last_ten_line_counts[$ten_minutes_ago_idx]}) / 10" | bc -l`
                echo "$per_minute per minute"
        fi

        #echo "${last_ten_line_counts[$idx]} - ${last_ten_line_counts[$ten_minutes_ago_idx]}" 
        #echo "idx $idx ten_minutes_ago_idx $ten_minutes_ago_idx"
        #for i in {0..9}; do
        #       echo ${last_ten_line_counts[$i]}
        #done

        (( idx++ )) 
        let idx=$idx%10
        sleep 60

done