Shell Programming and Scripting

#! /bin/bash
while read x
do
    echo $x
    echo $x | cut -d_ -f2 | egrep -q "20[0-9]{2}(0[1-9]|1[0-2])(0[1-9]|[12][0-9]|3[01])"
    [ $? -eq 0 ] && echo "Start date - correct format" || echo "Start date - not correct format"
    echo $x | cut -d_ -f3 | egrep -q "20[0-9]{2}(0[1-9]|1[0-2])(0[1-9]|[12][0-9]|3[01])"
    [ $? -eq 0 ] && echo "End date - correct format" || echo "End date - not correct format"
    echo
done < inputfile

while IFS='_' read v1 v2 v3
do
        echo $v1 $v2 $v3
done < infile