How can you read a files MIME-type in objective-c

I was using the answer provided by slf in a cocoa app (not iPhone) and noticed that the URL request seems to be reading the entire file from disk in order to determine the mime type (not great for large files).

For anyone wanting to do this on the desktop here is the snippet I used (based on Louis's suggestion):

NSString *path = @"/path/to/some/file";

NSTask *task = [[[NSTask alloc] init] autorelease];
[task setLaunchPath: @"/usr/bin/file"];
[task setArguments: [NSArray arrayWithObjects: @"-b", @"--mime-type", path, nil]];

NSPipe *pipe = [NSPipe pipe];
[task setStandardOutput: pipe];

NSFileHandle *file = [pipe fileHandleForReading];

[task launch];
[task waitUntilExit];
if ([task terminationStatus] == YES) {
    NSData *data = [file readDataToEndOfFile];
    return [[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding] autorelease];
} else {
    return nil;
}

If you called that on a PDF file it would spit out: application/pdf