Question

How can I remove last line in a file in iOS.

Below is the code that let’s me go to the end of file but then I don’t know how to remove that last line.

NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];

//make a file name to write the data to using the documents directory:
NSString *file = [NSString stringWithFormat:@"%@/%@.daa", documentsDirectory, MFILE_NAME];

NSFileHandle *aFileHandle = [NSFileHandle fileHandleForWritingAtPath:file]; 
//setting aFileHandle to write at the end of the file
[aFileHandle truncateFileAtOffset:[aFileHandle seekToEndOfFile]];

Thanks for your help.

Answer 1

Ok, after some documentation reading this is what I ended up with:

    NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *file = [NSString stringWithFormat:@"%@/%@.txt", documentsDirectory, @"file_name"];

    NSData *orgData = [NSData dataWithContentsOfFile:file];

    //Because there is only one char on my last line I make a range from 0 to length of data - 1 byte.
    NSRange range = {0, [orgData length]-1};

    NSData* shortData = [[NSData dataWithContentsOfFile:file] subdataWithRange:range];

    [shortData writeToFile:file atomically:YES];

If you know a better way please let me know.