Vi vs Vim – Understanding the Differences

vi is (also) a POSIX standard editor. There are plenty of implementations and vim is likely the most popular.

While many traditional Unix compliant OSes provide vi implementations very close to the standard, vim has added a lot of extra features that make it a double-edged sword.

Of course, these extensions are usually designed to ease the editing process and provide useful features and functionalities. However, once you are used to some of them (not the cosmetic ones like syntax coloring but those that change the editor's behavior) you can easily forget they are specific; and using a different implementation, including the ones based on the original BSD code can be very frustrating. The opposite is also true.

This is quite similar to the issue that happens with scripts using non POSIX bashisms faced to more orthodox shell implementations like dash or ksh.

That's a bit like asking what the difference is between a beaten up Datsun 120Y & a Porsche!

Vim has a multitude of features not offered by plain old vi:-

• Multiple windows - horizontal, vertical & tabs.
• Visual highlighting.
• Online help via the :help command.
• Record macros into a register that you can then execute.
• Undo (and redo) multiple times, rather than old vi's insane undo toggle.
• Command line history, search history.
• An entire language embedded along with a host of available functions, eg getcwd()
• Vastly expanded pattern matching.
• Word completion via ctrl-P & ctrl-N.
• A built in file navigator (a little clunky, but can be useful).
• The ESC key actually quits commands you were trying to, well, escape from instead of (insanely) running them as vi does.
• Ability to run commands on all buffers, args or windows via bufdo, argdo & windo.

I could rave on for much longer than this, vim has so many more features than plain old vi that there's really no comparison.

PS - To actually use plain old vi, you'd have to be working on a legacy Unix system, e.g. Solaris (sorry guys, it's going that way). You may well be using vim when you think you're using vi, as most Linux distros simply map vi to vim. If :help works, or multiple undos work, or :version works, you're using vim, not vi!