Objective-C how to read data from standard input and ignore extra (unneeded) characters

Question

I am currently using the following code to read the first character from the standard input (after a prompt):

NSFileHandle *stdIn = [NSFileHandle fileHandleWithStandardInput];
    NSString* input = [[NSString alloc]
        initWithData:[stdIn readDataOfLength:1]
        encoding:NSUTF8StringEncoding];

However, after the program completes, all the extra characters get interpreted by the command line (bash, in this case). For example, the prompt is

File already exists, do you want to overwrite it? [y/N]

and if I input noooooo, bash says -bash: oooooo: command not found after the program finishes. How do I avoid this? Using [stdIn readDataToEndOfFile] does not work, expectedly.

I could use [stdIn readToEndOfFileInBackgroundAndNotify], but if I need to get user input from such a prompt again, it wouldn't be possible.

Answer 1

If you want to keep it strictly in Objective C, you can always do:

NSFileHandle *kbd = [NSFileHandle fileHandleWithStandardInput];
NSData *inputData = [kbd availableData];
NSString *option = [[[NSString alloc] initWithData:inputData 
                 encoding:NSUTF8StringEncoding] substringToIndex:1];
NSLog(@"%@",option);