Min Length Address Bash Script

#/bin/bash
source bitcoin.sh

minlen=100;
i=0;
while [ 1 ]; do
    mid=$(echo "obase=16; $i" | bc)
    midlen=$(printf $mid | wc -c)
    extra=$(expr 40 - $midlen)
    mid=$(printf %0$(echo $extra)d)$mid
    addr=$(hexToAddress $mid)
    len=$(printf $addr | wc -c)
    if [ $len -le $minlen ]; then
        echo $len
        echo $addr
        minlen=$len
    fi

    # sleep 0.1
    let i+=1;
done