ファイルからすべての行を取得し、文字の置換やテキストの追加などの変更を加えてから、ファイルを保存します。
NSString *objPath = [[NSBundle mainBundle] pathForResource:@"textfile" ofType:@"txt"];
NSData *objData = [[NSData alloc] initWithContentsOfFile:objPath];
NSString *objString = [[NSString alloc] initWithData:objData encoding:NSUTF8StringEncoding];
NSMutableArray *lines = [NSMutableArray arrayWithArray:[objString componentsSeparatedByString:@"\n"]];
for (int i = 0; i < lines.count; i++) {
NSString *oneLine = [lines objectAtIndex:i];
if (oneLine.length < 2) {
continue;
}
oneLine = [NSString stringWithFormat:@"/%@", oneLine];
oneLine = [oneLine stringByReplacingOccurrencesOfString:@"`" withString:@"\`"];
[lines replaceObjectAtIndex:i withObject:oneLine];
}
NSString *finalString = [lines componentsJoinedByString:@"\n"];
//save the file