Create and read a text file

I am looking 开发者_开发知识库to create a text file on my iPhone programmatically and also write some data onto the file. How can I read the text file manually?

Use NSString's initWithContentsOfFile:encoding:error: to read the file, then use stringByAppendingFormat: to add some data, and then use writeToFile:atomically:encoding:error: to write it on disk.