#!/path/to/perl
# This is web_update.pl
$fileName="/path/to/file";
# We will check if this file was modified 
# more than one day ago
if( -M $fileName > 1 )
{ # mail the webmaster
open MAIL, "|mail webmaster\@your.domain.com";
  print MAIL $fileName." has not been 
  modified in the last day\n";
close MAIL;
}