if you're using vi

Vim is backwards compatible with vi. Switching from vi to Vim is easy: you can keep all the things that Vi offers and gain a large range of new features. Any one of these features may be a reason to start using Vim. A few are listed below, but a much more comprehensive list is in the Vim documentation, under :help vi_diff.

• unlimited undo

  You can do xxxx and undo each of the four deletes. When was the last time you typed "jjjj" and then found out the caps lock key was on? You accidentally joined five lines together, and Vi can undo only the last command. In Vim you can undo all four "J" commands and get your original text back.

• portability

  Vi is only available on Unix. Vim works on MS-Windows, Macintosh, Amiga, OS/2, VMS, QNX and other systems. And also on every Unix system.

• syntax highlighting

  Vim can be programmed to highlight portions of the buffer in different colors or styles, based on the type of file being edited. There are hundreds of syntax highlighting rulesets bundled with Vim.

• GUI

  Vim works well at a console, but it can run natively in many GUIs, including X Windows, Mac OS, and Microsoft Windows. It uses native GUI widgets for scrolling, dividing buffers, and menuing. It can also talk to the clipboard.

• vi compatibility mode

  In a pinch, you can force Vim to act like vi. All of the improvements and bug-fixes in Vim that make it incompatible with vi are turned off, and you're left with a 100% vi-compatible editor.