They are completely compatible for ordinary text editing. I suggest you use nvi . I suggest you avoid replace mode for now. In command mode, every key you type is a command. A file is a named, persistent collection of data.
Files remain from one login session to the next.
A directory is a named, persistent, collection of files and directories. In some operating systems, directories are called folders . Luckily, you don't need to remember where your home directory is. If you don't specify a directory, chdir will move you to your home directory. If you prefer, you can say cd instead of chdir .