Vim, or Vi Improved, is an extremely powerful text editor that lets you do almost everything using keyboard shortcuts. You can replace text in a document, move or delete lines, automate edits and more without ever reaching for the mouse. Vim is the favorite source code editor of programmers but there's no reason why you cannot use the editor for your regular text-editing tasks from writing down ideas to composing long emails.
If you have always used a graphic text editor like Notepad or TextEdit, you are likely to find Vim confusing but spend some time with the editor and it will be difficult for you to go back. Entire books have been written on Vim but just learn the basic commands, practice daily and you'll find yourself more efficient and productive.
Here are a list of online tutorials and other helpful resources to help you learn Vim.
1. OpenVim – An interactive tutorial for learning the basics of Vim. Switch to the Practice page to test your existing Vim skills.