vim

When connecting to a remote system, a shell (text-only command-line) will be the only interface you'll often have. Even worse, you may not have user-friendly text-based editors (e.g. nano) installed when you need to make a quick change. However, you'll need to look hard to find a system that doesn't have vi or vim (vi iMproved) installed.

This editor may seem very unfriendly at first, but if it were really unusable, it wouldn't be so popular among developers and system administrators (why do they use vi?). From a practical perspective, it's worth knowing the basics because that's the editor you can always rely on, on any unix-based system.

To create a new file or open an existing file, just pass it as an argument.

vi myFile

You'll see the empty file first.

You can't type anything yet, though, because the editor is not waiting for your text input. By default it will be in a "command" mode when vi waits for a command and not an "insert" mode when it's expecting you to enter text. Right now you could give it one of many commands:

• i – insert text before cursor
• o – open a new line after the current one
• dd – delete current line and dozens of others

Let's suppose we want to save a file with the text "Hello, world" inside. Press "i" once. The editor will switch into the insert mode:

Now whatever you type will be actually entered as text. Type "Hello, world". How do you save it now? Whatever you press now will be taken not as a command (save, exit, etc) but as text. To get back to the command mode press ESC. Now you're back in the command-mode.

Now we can tell vi to save the file. Press colon (:) and then w ("w" stands for "write").After you press Enter, the file will be written and you'll see the corresponding message.

Now we need to quit the editor. Type :q followed by Enter. (If you needed to quit without saving changes, you'd need to do :q!).

This is the absolute minimum you need to know to make a basic edit using vi. Print a cheat sheet and practice using vi on a few files.