while (<FILE>) {
    if (/foo/) {
        $count++;
        print "$count so far.\n";
    }
}

##</code><code>##

while (<FILE>) {
    while (/foo/g) {
        $count++;
        print "$count so far.\n";
    }
}

##</code><code>##

while (<FILE>) {
 $count++ while /foo/g; 
}
print $count;