Correct numbers of list

numbering.sh

#!/bin/bash

number=1

while read line
do
echo $line | grep -E '^[0-9][0-9]*' > /dev/null
if [ "$?" = "0" ]; then
    echo $line | sed "s/^[0-9][0-9]*\./$number\./"
    number=`echo $number+1|bc`
else
    echo $line
fi
done

example:

echo '1. foo                                                                                                                                                                          17:55:10
quote> 
quote> 3. bar
quote> 
quote> 4. baz' | ~/bin/numbering.sh 
1. foo

2. bar

3. baz