将NSString参数传递给NSTask时出错

Question

我正在尝试通过OSX应用程序中通过NSTask执行的pmset安排关机事件。

 NSCalendar *cal = [NSCalendar new];
NSDate *dateNext = [date dateByAddingTimeInterval:120];

NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:@"MM/dd/YYYY HH:mm:ss"];
NSString* dS = [df stringFromDate:dateNext];

//# pmset schedule shutdown "MM/DD/YYYY HH:MM:SS"

NSString* dateString = [NSString stringWithFormat:@"\"%@\"", dS];
NSLog(@"Date to set %@", dateString);

int pid = [[NSProcessInfo processInfo] processIdentifier];
NSPipe *pipe = [NSPipe pipe];
NSFileHandle *file = pipe.fileHandleForReading;
NSTask *task = [[NSTask alloc] init];
task.launchPath = @"/usr/bin/pmset";
NSArray *args = [NSArray arrayWithObjects:@"schedule",@"shutdown", dateString, nil];

[task setArguments:args];
task.standardOutput = pipe;
[task launch];

NSData *data = [file readDataToEndOfFile];
[file closeFile];

NSString *out = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
NSLog (@"Result:\n%@", out);

日志显示如下：

2019-09-12 12:38:53.470793+0100 TheApp[51008:4925389] Date to set "09/12/2019 12:40:53"
2019-09-12 12:38:53.518372+0100 TheApp[51008:4925389] Result:
Error: Badly formatted date (2)
Error parsing scheduled event.

正如pmset所要求的那样， dateString参数似乎在引号之间的格式正确，但是我一直收到这种错误。 NSTask是否缺少某些参数？

谢谢。