$logfile="log.txt";
$error="DOWN";
$warn="PROBLEM";
$redbutton="\<img src\=\'default_files/perlredblink2\.gif'>";
$greenbutton="\<img src\=\'default_files/perlgreenblink\.gif'>";
$yellowbutton="\<img src\=\'default_files/perlyellowblink\.gif'>";

open LOG, $logfile or die "Cannot open $logfile for read :$!";

@logarray=<LOG>;   # dumps all of $logfile into @logarray

if (@logarray eq $error) {
  print "<!--Content-type: text/html-->\n";
     print "$redbutton";
}
elsif (@logarray eq $warn) {
print "<!--Content-type: text/html-->\n";
     print "$yellowbutton";
}
else {
print "<!--Content-type: text/html-->\n";
     print "$greenbutton";
}