how to write script to change email address

we have 4000 html pages that need an email address changed.

eg) company@yahoo.com to company@hotmail.com

we only want the file modified date to be changed when there has been a change to the file.

Should I be using grep?

I fairly new to UNIX and was told to using something like this

find /qlinx/common/quicklinks/docs/700_799/ -name "*.htm" -type f | \
xargs perl -pi -e 's/\/company-information\/legal-and-regulatory/\/legal-and-regulatory/g'

however this changes the file modified date weather or not information was change

Please define what constitutes a "change to the file" and precisely how you detect this change? In general "change" needs a timebase.

the script will have to check each html page to see if it has the email address that needs to be replaced with the new email address. However, I do not want the file modified date to change unless the email address has been changed to the new address.