Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

This is a bit tricky. Instead of writing

    @ok = `grep @opts '$search_string' @filenames`;

You have to do this:

    my @ok = ();
    if (open(GREP, "-|")) {
        while (<GREP>) {
            chomp;
            push(@ok, $_);
        }
        close GREP;
    } else {
        exec 'grep', @opts, $search_string, @filenames;
    }

Just as with system(), no shell escapes happen when you exec() a list.

There are more examples of this Safe Pipe Opens.