Fletch had a good suggestion, but the results it returns are not the same as the find command, since the find command will return a count of all occurance, which may or may not be important to the problem at hand. This code block will give you a count of all the times the string occurs in a file.

my $file = "/path/to/file/and/filename";
open(LOG,"$file") or die;
my $match_count;
while(<LOG>) {
    my (@matches) = $_ =~ m/(127\.0\.0\.1)/g;
    $match_count += scalar(@matches);
}
print $match_count , "\n";
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Try to avoid system calls completely if it can helped to provide more portability and generally faster safer programs.