弱いかな？
package FileLock;
use IO::File;
my $CAT= '/bin/cat';
sub open_w {
my $filename= shift;
mkdir($filename)unless -d $filename;
my $base= sprintf("%s.%s.",time,$$);
my $cnt= 0;
$cnt++ while(-f "$filename/$base$cnt");
return IO::File->new("$filename/$base$cnt",'>>');
}
sub open_r {
my $filename= shift;
return IO::File->new("|$CAT $filename/*");
}
1;